JLG 20VP Service Manual

Service and Maintenance Manual

ANSI

Model

10VP
15VP
20VP

3120728

June 14 2001

FOREWORD

The purpose of this manual is to provide users with the operating procedures essential for the promotion of
proper machine operation for its intended purpose. It is important to over-stress proper machine usage. All
information in this manual should be READ and UNDERSTOOD before any attempt is made to operate the
machine. YOUR OPERATING MANUAL IS YOUR MOST IMPORTANT TOOL - Keep it with the machine.

REMEMBER ANY EQUIPMENT IS ONLY AS SAFE AS THE OPERATOR.

BECAUSE THE MANUFACTURER HAS NO DIRECT CONTROL OVER MACHINE APPLICATION AND
OPERATION, PROPER SAFETY PRACTICES ARE THE RESPONSIBILITY OF THE USER AND HIS OPER­ATING PERSONNEL.

ALL INSTRUCTIONS IN THIS MANUAL ARE BASED ON THE USE OF THE MACHINE UNDER PROPER
OPERATING CONDITIONS, WITH NO DEVIATIONS FROM THE ORIGINAL DESIGN. ALTERATION AND/
OR MODIFICATION OF THE MACHINE IS STRICTLY FORBIDDEN, WITHOUT WRITTEN APPROVAL
FROM JLG INDUSTRIES, PER OSHA REGULATIONS.

THIS "SAFETY ALERT SYMBOL" IS USED TO CALL ATTENTION TO POTENTIAL HAZARDS
WHICH MAY LEAD TO SERIOUS INJURY OR DEATH IF IGNORED.

Safety of personnel and proper use of the machine are of primary concern, DANGER, WARNING, CAUTION,
IMPORTANT, INSTRUCTIONS and NOTE are inserted throughout this manual to emphasize these areas.

They are defined as follows:

DANGER INDICATES AN IMMINENTLY HAZARDOUS SITUA­TION WHICH, IF NOT AVOIDED WILL RESULT IN SERIOUS
INJURY OR DEATH.

CAUTION INDICATES A POTENTIALLY HAZARDOUS SITUA­TION WHICH, IF NOT AVOIDED, MAY RESULT IN MINOR OR
MODERATE INJURY. IT MAY ALSO BE USED TO ALERT
AGAINST UNSAFE PRACTICES.

Also in this Manual "Notes:" are used to provide infor­mation of special interest.

JLG INDUSTRIES, INC. MAY HAVE ISSUED SAFETY RELATED BULLETINS FOR YOUR JLG PRODUCT. CONTACT JLG INDUS­TRIES, INC. OR THE LOCAL AUTHORIZED JLG DISTRIBUTOR FOR INFORMATION CONCERNING SAFETY RELATED BULLE­TINS WHICH MAY HAVE BEEN ISSUED FOR YOUR JLG PRODUCT. ALL ITEMS REQUIRED BY THE SAFETY RELATED
BULLETINS MUST BE COMPLETED ON THE AFFECTED JLG PRODUCT.

WARNING INDICATES A POTENTIALLY HAZARDOUS SITU­ATION WHICH, IF NOT AVOIDED COULD RESULT IN SERI­OUS INJURY OR DEATH.

IMPORTANT OR INSTRUCTIONS PROCEDURES ESSENTIAL
FOR SAFE OPERATION AND WHICH, IF NOT FOLLOWED
MAY RESULT IN A MALFUNCTION OR DAMAGE TO THE
MACHINE.

Due to the continuous product improvements, JLG Industries, Inc. reserves the right to make specification changes without
prior notification. Contact JLG Industries, Inc. for updated information.

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INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

A. GENERAL

This section contains the general safety precautions
which must be observed during maintenance of the aerial
platform. It is of utmost importance that maintenance per­sonnel pay strict attention to these warnings and precau­tions to avoid possible injury to themselves or others or
damage to the equipment. A maintenance program must
be established by a qualified person and must be followed
to ensure that the machine is safe to operate.

MODIFICATION OF THE MACHINE WITHOUT CERTIFICATION BY
A RESPONSIBLE AUTHORITY THAT THE MACHINE IS AT LEAST
AS SAFE AS ORIGINALLY MANUFACTURED IS A SAFETY VIOLA­TION.

The specific precautions to be observed during machine
maintenance are inserted at the appropriate point in the
manual. These precautions are, for the most part, those
that apply when servicing hydraulic and larger machine
component parts.

Your safety, and that of others, is the first consideration
when engaging in the maintenance of equipment. Always
be conscious of component weight and never attempt to
move heavy parts without the aid of a mechanical device.
Do not allow heavy objects to rest in an unstable position.
When raising a portion of the equipment, ensure that ade­quate support is provided.

SINCE THE MACHINE MANUFACTURER HAS NO DIRECT CON­TROL OVER THE FIELD INSPECTION AND MAINTENANCE,
SAFETY IN THIS AREA IS THE RESPONSIBILITY OF THE OWNER/
OPERATOR.

C. MAINTENANCE

FAILURE TO COMPLY WITH SAFETY PRECAUTIONS LISTED IN
THIS SECTION COULD RESULT IN MACHINE DAMAGE, PERSON­NEL INJURY OR DEATH AND IS A SAFETY VIOLATION.

• REMOVE ALL RINGS, WATCHES, AND JEWELRY
WHEN PERFORMING ANY MAINTENANCE.

• DO NOT WEAR LONG HAIR UNRESTRAINED, OR
LOOSE FITTING CLOTHING AND NECKTIES WHICH
ARE APT TO BECOME CAUGHT ON OR ENTANGLED
IN EQUIPMENT.

• OBSERVE AND OBEY ALL DANGER, WARNING, CAU­TION AND OTHER INSTRUCTIONS ON MACHINE
AND IN SERVICE MANUAL.

• KEEP STANDING SURFACES AND HAND HOLDS
FREE OF OIL, GREASE, WATER, ETC.

• NEVER WORK UNDER AN ELEVATED PLATFORM
UNTIL PLATFORM HAS BEEN SAFELY RESTRAINED
FROM ANY MOVEMENT BY BLOCKING OR OVER­HEAD SLING.

• BEFORE MAKING ADJUSTMENTS, LUBRICATING OR
PERFORMING ANY OTHER MAINTENANCE, SHUT
OFF ALL POWER CONTROLS.

•BATTERY SHOULD ALWAYS BE DISCONNECTED
DURING REPLACEMENT OF ELECTRICAL COMPO­NENTS.

• KEEP ALL SUPPORT EQUIPMENT AND ATTACH­MENTS STOWED IN THEIR PROPER PLACE.

• USE ONLY APPROVED, NONFLAMMABLE CLEANING
SOLVENTS.

B. HYDRAULIC SYSTEM SAFETY

1. It should be particularly noted that the machines
hydraulic systems operate at extremely high and
potentially dangerous pressures. Every effort should
be made to relieve any system pressure prior to dis­connecting or removing any portion of the system.

2. Relieve system pressure by activating the lift DOWN
control with the platform completely lowered to
direct any line pressure back into the return line to
the reservoir. Pressure feed lines to system compo­nents can then be disconnected with minimal fluid
loss.

3120728 – JLG Lift – a

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

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b – JLG Lift – 3120728

EFFECTIVITY CHANGES

September 15, 1997 – Original Issue of Manual

January 10, 1998 – Change 1– Pages Affected: Revision Log - Page c

Table of Contents - Page ii

Section 3 - Pages 3-8 & 3-9

February 7, 2000 – Revised – Pages Affected: Section-1, Page 1-5, Table 1-5.

Section-2, Page 2-18, Table 2-3.

(removed lube check requirement for drive wheel gear box)

March 22, 2000– Revised – Added 20VP UL-EE Option.

September 8, 2000 – Revised Complete Manual

EFFECTIVITY PAGE

October 19, 2000 – Revised – Pages Affected:Section-2, Pages 2-20 thru 2-22 also 2-32 and 2-33.

Section-3, Page 3-16, added Table 3-3.

November 15, 2000 – Revised – Pages Affected:Section-1, Page 1-1

Section-2, Pages 2-33 & 2-34.

June 14, 2001 – Revised – Pages Affected:Section-2, Pages 2-23 thru 2-25

3120728 – JLG Lift – c

EFFECTIVITY PAGE

This page intentionally left blank

d – JLG Lift – 3120728

TABLE OF CONTENTS

SUBJECT - SECTION, PARAGRAPH PAGE NO.

SECTION INTRODUCTION - - MAINTENANCE SAFETY PRECAUTIONS

A General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .a

B Hydraulic System Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .a

C Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .a

Effectivity Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .c

SECTION 1 - SPECIFICATIONS

1.1 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.2 Component Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.3 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.4 Torque Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1.5 Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1.6 Hydraulic Pressure Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.7 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.8 Serial Number Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

SECTION 2 - SERVICE PROCEDURES

2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2.2 Servicing And Maintenance Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

2.3 Lubrication Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

2.4 Positioning Lift For Access To Components Located Under The Base Frame . . . . . . . . . . . . . . .2-4

2.5 Drive Motor Component Service Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.6 Platform Control Box Service Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

2.7 Battery Charger Assembly And Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2.8 Hydraulic Lift Cylinder - Removal, Inspection And Rebuild . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2.9 Mast Assembly And Disassembly Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-26

2.10 Mast To Base Frame Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-35

2.11 Mast Chains/cables And Sequencing Cables Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-36

2.12 Sequence Cable Replacement Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38

2.13 Preventive Maintenance And Inspection Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-40

SECTION 3 - TROUBLESHOOTING

3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

3.2 Troubleshooting Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.3 Hydraulic Circuit Checks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.4 Electrical Circuit Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.5 Troubleshooting Section - Table Of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15

3.6 Ohm Ratings For Various Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16

3.7 Main Power Circuit Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17

3.8 Drive Train Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-20

3.9 Mast Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

3.10 Hydraulic Leak Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-41

3.11 Base Frame Components Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-42

3120728 – JLG Lift – i

TABLE OF CONTENTS

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

1-1. Hydraulic Pressure Setting - Adjustment Screw Located at Base of Pump Motor . . . . . . . . . . . .1-3

1-2. Hydraulic Pressure Gauge Installation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-3. Torque Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1-4. Lubrication Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

2-1. Accessing Machine Underside Components by Lifting with a Fork Truck. . . . . . . . . . . . . . . . . . .2-4

2-2. Check Torque Limit Clutch - Torque Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2-3. Torque Limit Clutch - Adjustment Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-4. Brake Assembly Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-5. Brake Armature Plate & Brake Disk Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-6. Manual Release Brake Cable Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-7. Drive Motor Assembly Removal.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-8. Drive Motor Gear Box Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2-9. Gear/Pinion Shaft Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2-10. Drive Shaft Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-11. Drive Motor Brush Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2-12. Drive Motor Brush Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

2-13. Correct/Incorrect Brush Spring Bracket Positions.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-14

2-14. Platform Control Box Assembly (Exploded View). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

2-15. Platform Control - Circuit Board Component Wiring Connections. . . . . . . . . . . . . . . . . . . . . . . . . 2-17

2-16. Machine Positioned for Cylinder Removal.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2-17. Lift Cylinder Internal Component Assembly Cross-Section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-25

2-18. Mast Section - Assembly Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

2-19. 10VP Mast Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28

2-20. 15VP Mast Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29

2-21. 20VP Mast Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30

2-22. Mast Chain/Cable/Sequence Cable Adjustment Components. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-37

3-1. LED Battery/Fault Code Indicator Strip on Platform Controller Box. . . . . . . . . . . . . . . . . . . . . . . . 3-2

3-2. Overview of Standard Electrical System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6

3-3. VP Electrical Diagram. (VP Series - Standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

3-4. Overview of VP UL-EE Approved Optional Electrical System. . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3-5. VP Electrical Diagram. (with UL-EE Approved Option) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

3-6. Hydraulic Diagram. (VP Series) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-14

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1-1. Machine GVW and Wheel Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-2. Hydraulic Oil Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1-3. Lubrication Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1-4 Machine Interlock Switch Operating Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1-5. Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-6 Lubrication Intervals for Various Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

2-1 Chain Stretch Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

2-2 VP Series Mast Component Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-26

2-3 Preventive Maintenance & Inspection Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-41

3-1 MC-1 WARNING CODES (Indicated by 3 beeps, then slow flashing LED’s). . . . . . . . . . . . . . . . .3-3

3-2 MC-1 ERROR CODES (Indicated by rapid LED flashing and periodic beep) . . . . . . . . . . . . . . . . 3-4

3-3 Ohm Ratings for Various Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16

3-4 Unit will not Power Up From Ground Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

3-5 No Power At Platform Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18

3-6 Won’t Drive. (Platform Lowered or Elevated) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

3-7 Elevation Switch Circuit Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

3-8 Brake Limit Switch Circuit Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

ii – JLG Lift – 3120728

TABLE OF CONTENTS

3-9 Drive Motor/Circuit Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21

3-10 Brake Switch/Circuit Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

3-11 Won’t Drive with Platform Elevated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22

3-12 Tilt Sensor Circuit Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22

3-13 PHP Limit Switch Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23

3-14 Won’t Climb Grade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

3-15 Drives In Opposite Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25

3-16 Only Drives A Short Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

3-17 E-Stop and Key Switch Circuit Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27

3-18 Won’t Drive Straight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

3-19 Noise from Drive Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29

3-20 Platform Will Not Lift Up Using Platform Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

3-21 Pump Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-31

3-22 Pump Valves Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32

3-23 Platform Will Not Lower Using Platform Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33

3-24 Unit Will Not Lift Up From Ground Control Toggle Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-34

3-25 Unit Will Not Lower From Ground Control Toggle Switch.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-35

3-26 Platform Will Not Lower Manually. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

3-27 Platform Lift Up and Down Jerky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-37

3-28 Mast Noisy when Lifting and Lowering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-38

3-29 Platform (Mast) Won’t Stay Elevated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-39

3-30 Platform (Mast) Descends Too Slowly.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

3-31 Hydraulic Leak Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-41

3-32 Caster Wheels Not Operating Freely. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-42

3-33 Pot Hole Protection (PHP) Bars Will Not Set. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-42

3120728 – JLG Lift – iii

TABLE OF CONTENTS

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iv – JLG Lift – 3120728

SECTION 1. SPECIFICATIONS

SECTION 1 - SPECIFICATIONS

1.1 CAPACITIES

System Voltage

All VP Models –24 Volt DC (2 - 12 volt DC batteries)

Hydraulic Oil Reservoir

All VP Models – 5 qts. U.S. (4.7 ltr.)

1.2 COMPONENT DATA

Hydraulic Pump/Pump Motor Assembly

Pump Motor - 24 Volt DC motor

Pump Displacement –

10 & 15VP – .098 cu. in./rev. (1.6cc/rev.)

20VP – .049 cu. in./rev. (0.8cc/rev )

Pump Output (Max.) –

10 & 15VP - 1.20 gpm @ 2200 psi

20VP – 0.65 gpm @ 2200 psi

Hydraulic System Pressure Setting –

10 & 15VP - 1000 psi (68.95 bar)

20VP - 2500 psi (172.3 bar)

Rear Wheel Drive Motors

DriveMotors -

24 Volt DC w/perm. magnet

Right angle gear

Maintenance free sealed gear

Brake shaft and drive shaft,Integral to Motor

Parking Brake (must be released for pushing)

Batteries/Battery Charger

Batteries (2) – 12 Volt / 80 Amp Hour –

Deep CycleMarine - RV

Battery Charger –

U.S.A./CAN. –120 Volt A.C. / 60 Hz input

Brazil - 220 Volt A.C./ 60 Hz input

24 volt, 10 amp output -

with 2 amp finish

Reset Circuit Breaker

Automatic Charge Circuit

Plug Interlock Circuit

1.3 PERFORMANCE DATA

Platform Capacity(All Platforms except
Extendible)

10VP –350 lbs. (160 kg)

15VP –350 lbs. (160 kg)

20VP –350 lbs. (160 kg)

Extendible Platform Capacity

ANSI (U.S.) – 300 lbs. (136 kg)

CSA (CAN.) – 250 lbs. (114 kg)

Platform Size

Standard Platform – 26 in. x 26 in.

(66cm) x (66cm)

Machine Height (In Stowed Position)

VP Series - 79 in. (201cm) height

Tab le 1 - 1 .

Machine GVW and Wheel Loads

VP MODEL CONFIG. GVW (no load)

10VP ANSI (U.S.) 930 lb. (422 kg) 424 lb. 216 lb. 76 psi 102 psi

CSA (CAN.) 930 lb. (422 kg) 424 lb. 216 lb. 76 psi 102 psi

15VP ANSI (U.S.) 1,355 lb. (615 kg) 604 lb. 249 lb. 108 psi 117 psi

CSA (CAN.) 1,425 lb. (647 kg) 630 lb. 257 lb. 113 psi 121 psi

20VP ANSI (U.S.) 1,910 l b. (867 kg) 750 lb. 400 lb. 134 psi 188 psi

CSA (CAN.) 2,100 lb. (953 kg) 774 lb. 470 lb. 140 psi 220 psi

DRIVE WHEEL

(ea) w/rated load

CASTER

(ea) w/rated load

PSI

(Drive)

PSI

(Caster)

3120728 – JLG Lift – 1-1

SECTION 1 - SPECIFICATIONS

Base Footprint

VP Series - 32 in. (81cm) width 56 in. (1.42m) length

Max. Platform Height (mast extended)

10VP – 10 ft. 6 in.(3.2m)

15VP – 15 ft.(4.5m)

20VP – 19 ft. 9 in.(5.9m)

Platform Working Height (average)

10VP –16 ft. 6 in.(4.8m)

15VP –21 ft.(6.4m)

20VP –25 ft. 9 in.(7.6m)

Machine Drive Speed (max.)*

Platform Lowered - 2 mph (3.22 kph)

Platform Elevated - 0.5 mph (.81 kph)

(reduced by limit switch)

* Variable to maximum with speed cut back.

Amperage Draw (average)

Lift - 12 amps.Drive - 20 amps.

Interlock Switch Operating Conditions

Table 1-4. shown, lists machine response to various inter­lock switch positions.

1.5 LUBRICATION

Hydraulic Oil

Hydraulic oils must have anti-wear qualities at least to API
Service Classification GL-3, and sufficient chemical stabil­ity for mobile hydraulic system service. JLG Industries,
recommends Mobilfluid 424 hydraulic oil, which has an
SAE viscosity of 10W-30 and a viscosity index of 152.

For cold weather applications, i.e. when temperatures
remain consistently below +20°F (–7°C) JLG recom­mends using Mobil DTE 13 hydraulic oil.

Aside from JLG recommendations, it is not advisable to
mix oils of different brands or types, as they may not con­tain the same required additives or be of comparable vis­cosities. If use of hydraulic oil other than Mobilfluid 424 is
desired, contact JLG Industries for proper recommenda­tions.

Table 1-2. Hydraulic Oil Operating Range

HYDRAULIC SYSTEM OPERATING

TEMPERATURE RANGE

0 ° F t o +2 3 ° F

(-18° C to -5° C)

0° F to +210° F

( -1 8 ° C t o +9 9 ° C )

50° F to 210° F

(+10° C to +210° C)

SAE VISCOSITY

GRADE

10W

10W-20, 10W-30

20W-20

Lubrication Specifications

1.4 TORQUE REQUIREMENTS

When maintenance becomes necessary or a fastener has
loosened, refer to the Torque Chart, Figure 1-3., Torque
Chart. to determine proper torque value.

Table 1-4. Machine Interlock Switch Operating Conditions.

Mast Elevation

mast retracted bars raised (not tilted) engaged Full Dr ive and Lift
mast retracted bars raised (not tilted) disengaged Drive and Lift Disabled
mast extended bars lowered (not tilted) engaged Drive 25% maximum
mast extended bars raised (blocked) (not tilted) engaged Drive Disable d
mast extended bars lowered (tilt) engaged Drive and Lift disabled
mast retracted bars raised (tilt) engaged Lift Disabled

mast retracted

Drive Cutout

(PHP System)

bars raised/battery charger

plugged-in

Tilt Status Brake Status Controller Response

(not tilted) engaged Drive Disable d

Table 1-3. Lubrication Specifications

KEY SPECIFICATIONS

Multipurpose Grease having a minimum dripping point

MPG -

EPGL -

HO - Hydraulic Oil. ISO-Vg grade 32, 46.

of 350° F. Excellen t water resistance and adhe sive qual­ities, and being of extreme pressure type. (Timken OK
40 poun ds minimum.)

Extreme Pressure Gear Lube (oil) meeting API service
classification GL-5 or MIL-Spec MIL-L-2105.

1-2 – JLG Lift – 3120728

1.6 HYDRAULIC PRESSURE ADJUSTMENT

RETURN

SECTION 1 - SPECIFICATIONS

Adjust system pressure so that platform will raise with
rated capacity in platform.

The following are recommended factory pressure set­tings;

VP10,VP15 –1000 psi
VP20 – 2500 psi

Turning adjustment screw clockwise increases system
pressure, turning screw counterclockwise decreases
system pressure.

Make pressure adjustment with oil at normal operating
temperature. If pressure is set when oil is cold, platform
may not raise rated load after oil has warmed.

PRESSURE

ADJUSTMENT

SCREW

ADJUSTMENT

SCREW CAP

LINE

REPLACE ELBOW
WITH A T-FITTING

TO CONNECT

PRESSURE GAUGE

HERE

EXTEND

LINE

PRESSURE

GAUGE

Figure 1-2. Hydraulic Pressure Gauge Installation.

1.7 CYLINDER SPECIFICATIONS

NOTE: All dimensions are given in inches (in), with the met-

ric equivalent, centimeters (cm), given in parenthe­ses.

Table 1-5. Cylinder Specifications

Figure 1-1. Hydraulic Pressure Setting - Adjustment

Screw Located at Base of Pump Motor

(Remove Hex Head Cap as Shown)

ONLY OPEN HYDRAULIC SYSTEM LINES WITH THE MAST LOW-

DESCRIPTION

Lift Cylinder ­10VP

Lift Cylinder ­15VP

Lift Cylinder ­20VP

BORE

in./(cm)

1.50

(3.81)

1.50

(3.81)

1.50

(3.81)

STROKE

in./(cm)

54.50

(138.43)

54.50

(138.43)

54.50

(138.43)

ROD DIA.

in./(cm)

1.125
(2.86)

1.125
(2.86)

1.125
(2.86)

ERED TO RELIEVE PRESSURE IN THE SYSTEM. CAREFULLY
LOOSEN REQUIRED FITTINGS, WEAR SAFETY PROTECTION
EQUIPMENT WHEN WORKING WITH HYDRAULIC SYSTEMS.

Connect pressure gauge as shown in Figure 1-2., Hydrau­lic Pressure Gauge Installation.

1.8 SERIAL NUMBER LOCATION

For machine identification, a serial number plate is affixed
to the machine. The plate is located on the back of the
mast, just above the mast support bracket.

Select a T-Fitting to exactly match the thread size of the
pump (.562 x 18 THD), pressure line (.562 x 18 THD) and
gauge fitting as required.

3120728 – JLG Lift – 1-3

SECTION 1 - SPECIFICATIONS

Figure 1-3. Torque Chart.

1-4 – JLG Lift – 3120728

SECTION 1 - SPECIFICATIONS

6

1

2

3

Figure 1-4. Lubrication Chart.

Table 1-6.Lubrication Intervals for Various Components

ITEM COMPONTENT

1Hydraulic Oil

Drive Wheel

2

Bearings

Drive Wheel

3

Gear Box

4 Caster Axle s 2 - Grease Fitt ing MPG - Pressure Gun

5 Swivel Raceways 2 - Front Casters MPG - Pressure Gun

6 Mast Chains * 2 - Per Section

* Ap p li e s On l y t o Ma s t Se c ti o ns w i th C ha i ns .

Key to Lubricants: MPG - Multipurpose Grease

NO/TYPE

LUBE POINTS

F il l To Li n e o n
Reservoir
5 Qt. Reservoir

4 - Grease Fittings MPG- Pressure Gun

2 - Gear Box Gear Oil

HO - Hydra ulic Oil - See Sectio n 1.5, "Lubrication" in Service Manua l.
GEAR OIL - Good Quality Worm Gear Oil - SAE 90 - AGMA#5 - EP Compounded

LUBE/METHOD

HO - Check Hyd. Oil
L e ve l
HO - Change Hyd. Oil

Chain Lube - Brush or
Spray

3

MONTHS

150 Hrs.

✔

✔

✔

✔

4, 5

INTERVAL HOURS

6
MONTHS
300 Hrs.

1

YEAR

600 Hrs.

2

YEARS

1200 Hrs.

✔

COMMENTS

Check Hydraulic Oil every 10 hrs.
Change Hydr aulic Oil every 1 200
hrs.

Change only when serviced

requires 6 oz. (175 cc ’s) to fill.

Inspect, lubricate if dry or rusting.

Notes: 1. Be certain t o lubricate like items on each side of the machine.

2. Recommended lubricating intervals are based on nor mal use. If machine is subjected to severe operating conditions,

such as a high number of cycles, location, corrosive/dir ty environment, etc., user must adjust lubricating requirements accordingly.

3. Prior to checking hydraulic oil level, operate machine through one complete cycle of lift function (full up and down). Failure t o do s o wi l l
result in incorrect oil level reading on the hydraulic reservoir.

3120728 – JLG Lift – 1-5

SECTION 1 - SPECIFICATIONS

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1-6 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

SECTION 2. SERVICE PROCEDURES

2.1 GENERAL

This section provides general information to assist in the
performance of maintenance on the personnel lift.
Descriptions, techniques and specific procedures are
designed to provide the safest and most efficient mainte­nance for use by personnel responsible for ensuring the
correct installation and operation of machine components
and systems.

WHEN AN ABNORMAL CONDITION IS NOTED AND PROCEDURES
CONTAINED HEREIN DO NOT SPECIFICALLY RELATE TO THE
NOTED IRREGULARITY, WORK SHOULD BE STOPPED AND
TECHNICALLY QUALIFIED GUIDANCE OBTAINED BEFORE WORK
IS RESUMED.

2.2 SERVICING AND MAINTENANCE
GUIDELINES

General

The following information is provided to assist you in the
use and application of servicing and maintenance proce­dures contained in this chapter.

selves. As soon as a line or component is disconnected,
cap or cover all openings to prevent entry of foreign mat­ter.

Clean and inspect all parts during servicing or mainte­nance, and assure that all passages and openings are
unobstructed. Cover all parts to keep them clean. Be sure
all parts are clean before they are installed. New parts
should remain in their containers until they are ready to be
used.

Components Removal and Installation

Use adjustable lifting devices, whenever possible, if
mechanical assistance is required. All slings (chains,
cables, etc.) should be parallel to each other and as near
perpendicular as possible to top of part being lifted.

Should it be necessary to remove a component on an
angle, keep in mind that the capacity of an eyebolt or sim­ilar bracket lessens, as the angle between the supporting
structure and the component becomes less than 90
degrees.

If a part resists removal, check to see whether all nuts,
bolts, cables, brackets, wiring, etc., have been removed
and that no adjacent parts are interfering.

Component Disassembly and Reassembly

Safety and Workmanship

Your safety, and that of others, is the first consideration
when engaging in the maintenance of equipment. Always
be conscious of component weight. Never attempt to
move heavy parts without the aid of a mechanical device.
Do not allow heavy objects to rest in an unstable position.
When raising a portion of the equipment, ensure that ade­quate support is provided.

NEVER WORK UNDER AN ELEVATED PLATFORM UNTIL PLAT­FORM HAS BEEN SAFELY RESTRAINED FROM ANY MOVEMENT
BY BLOCKING OR OVERHEAD SLING.

Cleanliness

The most important single item in preserving the long ser­vice life of a machine is to keep dirt and foreign materials
out of the vital components. Precautions have been taken
to safeguard against this. Shields, covers, seals, and fil­ters are provided to keep the wheel bearings, mast sec­tions and oil supply clean; however, these items must be
maintained on a scheduled basis in order to function
properly.

At any time when oil lines are disconnected, clear adja­cent areas as well as the openings and fittings them-

When disassembling or reassembling a component, com­plete the procedural steps in sequence. Do not partially
disassemble or assemble one part, then start on another.
Always recheck your work to assure that nothing has been
overlooked. Do not make any adjustments, other than
those recommended, without obtaining proper approval.

Pressure-Fit Parts

When assembling pressure-fit parts, use an “anti-seize” or
molybdenum disulfide base compound to lubricate the
mating surface.

Bearings

When a bearing is removed, cover it to keep out dirt and
abrasives. Clean bearings in nonflammable cleaning sol­vent and allow to drip dry. Compressed air can be used
but do not spin the bearing.

Discard bearings if the races and balls (or rollers) are pit­ted, scored, or burned.

If bearing is found to be serviceable, apply a light coat of
oil and wrap it in clean (waxed) paper. Do not unwrap
reusable or new bearings until they are ready to install.

Lubricate new or used serviceable bearings before instal­lation. When pressing a bearing into a retainer or bore,

3120728 – JLG Lift – 2-1

SECTION 2 - SERVICE PROCEDURES

apply pressure to the outer race. If the bearing is to be
installed on a shaft, apply pressure to the inner race.

Gaskets

Check that holes in gaskets align with openings in the
mating parts. If it becomes necessary to hand-fabricate a
gasket, use gasket material or stock of equivalent material
and thickness. Be sure to cut holes in the right location, as
blank gaskets can cause serious system damage.

Bolt Usage and Torque Application

Use bolts of proper length. A bolt which is too long will
bottom before the head is tight against its related part. If a
bolt is too short, there will not be enough thread area to
engage and hold the part properly. When replacing bolts,
use only those having the same specifications of the origi­nal, or one which is equivalent.

Unless specific torque requirements are given within the
text, standard torque values should be used on heat­treated bolts, studs, and steel nuts, in accordance with
recommended shop practices. (See Figure 1-1.)

Hydraulic Lines and Electrical Wiring

Clearly mark or tag hydraulic lines and electrical wiring, as
well as their receptacles, when disconnecting or removing
them from the unit. This will assure that they are correctly
reinstalled.

Hydraulic System

Keep the system clean. If evidence of metal or rubber par­ticles is found in the hydraulic system, drain and flush the
entire system.

Disassemble and reassemble parts on clean work sur­face. Clean all metal parts with non-flammable cleaning
solvent. Lubricate components, as required, to aid assem­bly.

Lubrication and Servicing

Components and assemblies requiring lubrication and
servicing are shown in the Lubrication Chart, (See Figure
1-2.). Service applicable components with the amount,
type, and grade of lubricant recommended in this manual,
at the specified intervals. When recommended lubricants
are not available, consult your local supplier for an equiva­lent that meets or exceeds the specifications listed.

Batteries

Clean batteries, using a non-metallic brush and a solution
of baking soda and water. Rinse with clean water. After
cleaning, thoroughly dry batteries and coat terminals with
an anti-corrosion compound.

Mast Chain Inspection Procedure

MAST CHAINS TO BE INSPECTED AND LUBRICATED EVERY
THREE MONTHS.

Inspect mast chains for the following conditions:

Wear: Always inspect that segment of chain that operates
over a sheave. As the chain flexes over the sheaves, joints
and plate edges very gradually wear. Chain “stretch” can
be measured using a manufacturers wear scale or steel
tape. When chains have elongated 3% they must be
removed and replaced. Refer to Table 2-1 for proper chain
specifications and allowable stretch tolerances. Peening
and wear of chain plate edges are caused by sliding over
a chain worn contact face of a sheave, or unusually heavy
loads. All of the above require replacement of the chain
and correction of the cause. Chain side wear, noticeable
when pin heads and outside plates show a definite wear
pattern, is caused by misalignment of the sheave/chain
anchors and must be corrected promptly. Do not repair
chains; if a section of chain is damaged, replace the entire
chain set.

Rust and Corrosion: Rust and corrosion will cause a
major reduction in the load carrying capacity of the chain,
because these are primary reasons for side plate crack­ing. The initial lubrication at the factory is applied in a hot
dip tank to assure full penetration into the joint. Do not
steam clean or degrease chains. At time of chain installa­tion, factory lube must be supplemented by a mainte­nance program to provide a film of oil on the chains at all
times. If chains are corroded, they must be inspected,
especially the outside plates, for cracks in-line with the
pins. If cracks are found, replace the chain; if no cracks
are discovered, lubricate the chains by dipping in heated
oil, and reinstall on the machine. Keep chains lubricated.

Table 2-1. Chain Stretch Tolerance

Chain Size

.50" pitch 12" or 24 pitches . 24 in./12 in. span

.625 pitch 15" or 24 pitches .30 in./1 5 in. span

Fatigue Cracks: Fatigue is a phenomenon that affects
most metals, and is the most common cause of chain
plate failures. Fatigue cracks are found through the link
holes, perpendicular (90 degrees) from the pin in-line
position. Inspect chains carefully after long time use and
heavy loading for this type of crack. If any cracks are dis­covered, replace all chains, as seemingly sound plates
are on the verge of cracking. Fatigue and ultimate
strength failures on JLG Lifts are incurred as a result of
severe abuse as design specs are well within the rated lift­ing capacity of these chains.

Pin to Pin

Measurement

Allowable Stretch

2-2 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

Tight Joints: All joints in the leaf chain should flex freely.
On leaf chain, tight joints are usually caused by rust/corro­sion, or the inside plates “walking” off the bushing. Limber
up rusty/corroded chains (after inspecting care fully) with
a heavy application of oil (preferably a hot oil dip). Tap
inside “ walking” plates inward; if “walking” persists,
replace the chain. This type of problem is accelerated by
poor lubrication maintenance practice, and most tight
joint chains have been operated with little or no lubrica­tion. Tight joints on leaf chain are generally caused by:

a. Bent pins or plates.

b. Rusty joints.

c. Peened plate edges.

Oil rusty chains, and replace chains with bent or peened
chain components. Keep chains lubricated.

Protruding or Turned Pins: Chains operating with inade­quate lube generate tremendous friction between the pin
and plates (pin and bushing on leaf chain). In extreme
cases, this frictional torque can actually turn the pins in
the outside press-fit plates. Inspect for turned pins, which
can be easily spotted as the “V” flats on the pin heads are
no longer in line. Replace all chains showing evidence of
turned or protruding pins. Keep chains lubricated.

Chain Anchors and Sheaves: An inspection of the chain
must include a close examination of chain anchors and
sheaves. Check chain anchors for wear breakage and
misalignment. Anchors with worn or broken fingers should
be replaced. They should also be adjusted to eliminate
twisting the chain for an even load distribution.

Inspect the sheaves, sheave bearings, sheave grooves
and pins for extreme wear, replace as necessary. A worn
sheave can mean several problems, as follows:

a. Chains too tight.

b. Sheave bearings/pin bad.

c. Bent/misaligned chains.

Mast Cable Inspection Procedure

Inspection should be more frequent as cables approach
the end of their useful lives.

Only the surface wires of the cable require inspection, do
not attempt to open the cable. Any deterioration resulting
in any loss of original strength, such as described below,
shall be noted, and then a determination made if further
use would constitute a hazard.

Mast cables must be replaced after machine has been in
service for five (5) years, regardless of cable condition, or
sooner if conditions dictate.

Conditions such as the following shall be sufficient reason
for questioning continual use of the [cable] or increasing
the frequency of inspection:

1. In running ropes, six randomly distributed broken
wires in one lay or three broken wires in one strand
in one lay.

2. One outer wire broken at the point of contact with
the core of the rope which has worked its way out of
the rope structure and protrudes or loops out from
the rope structure. Additional inspection of this sec­tion is required.

3. Wear of one-third the original diameter of outside
individual wires.

4. Kinking, crushing, birdcaging or any other damage
resulting in distortion of the rope structure.

5. Evidence of any heat damage from any cause.

6. Reductions from nominal diameter of more than;

a. 1/64th in. (0.4mm) for diameters up to and

including 5/16th in. (8mm);

NOTE: A good indicator of a stretched extend/retract cable

is if the adjusting nuts are bottomed out. If no adjust­ment remains the cables have stretched and need
replacement.

Also check for cracked, bent, worn, severely corroded, or
improperly installed cable ends.

Inspect sheaves, sheave grooves, and sheave pins for
excessive wear, replace as necessary.

MAST CABLES ARE TO BE INSPECTED EVERY THREE MONTHS
OR MORE FREQUENTLY AS DESCRIBED FOLLOWING.

2.3 LUBRICATION INFORMATION

Hydraulic System

WEAR PROTECTIVE GLOVES TO PROTECT HANDS WHEN HAN­DLING CABLE.

The periodic inspection shall cover the entire length of the
cable. The inspection frequency shall be based on such
factors as expected cable life as determined by experi­ence on the particular application or similar installations,
severity of environment, percentage of capacity lifts, fre­quency rates of operation, and exposure to shock loads.

3120728 – JLG Lift – 2-3

The primary enemy of a hydraulic system is contamina­tion. Contaminants enter the system by various means,
e.g., using inadequate hydraulic oil, allowing moisture,
grease, filings, sealing components, sand, etc., to enter
when performing maintenance, or by permitting the pump
to cavitate due to insufficient system warm-up or leaks in
the pump supply.

The design and manufacturing tolerances of the compo­nent working parts are very close, therefore, even the
smallest amount of dirt or foreign matter entering a system

SECTION 2 - SERVICE PROCEDURES

can cause wear or damage to the components and gener­ally results in faulty operation. Every precaution must be
taken to keep hydraulic oil clean, including reserve oil in
storage.

Cloudy oils indicate a high moisture content which per­mits organic growth, resulting in oxidation or corrosion. If
this condition occurs, the system must be drained,
flushed, and refilled with clean oil.

It is not advisable to mix oils of different brands or types,
as they may not contain the same required additives or be
of comparable viscosities. Good grade mineral oils, with
viscosities suited to the ambient temperatures in which
the machine is operating, are recommended for use.

NOTE: Metal particles may appear in the oil of new

machines due to the wear-in of meshing compo­nents.

Hydraulic Oil

For best performance, JLG recommends the use of ISO­Vg grade 32, 46 oil with a viscosity range between 15-250
SUS at 100 degrees F (32-54 cST at 40 degrees C). Refer
to Section 1-5 of this Service Manual for recommended
hydraulic oils.

Changing Hydraulic Oil

Use of any of the recommended hydraulic oils eliminates
the need for changing the oil on a regular basis. If it is nec­essary to change the oil, use only those oils meeting or
exceeding the specifications appearing in this manual. If
unable to obtain the same type of oil supplied with the
machine, consult local supplier for assistance in selecting
the proper equivalent. Avoid mixing petroleum and syn­thetic base oils. JLG Industries recommends changing the
hydraulic oil annually.

Use every precaution to keep the hydraulic oil clean. If the
oil must be poured from the original container into
another, be sure to clean all possible contaminants from
the service container.

While the unit is shut down, a good preventive mainte­nance measure is to make a thorough inspection of all
hydraulic components, lines, fittings, etc., as well as a
functional check of each system, before placing the
machine back in service.

Lubrication Specifications

Specified lubricants, as recommended by the component
manufacturers, are always the best choice, however,
multi-purpose greases usually have the qualities which
meet a variety of single purpose grease requirements.
Should any question arise regarding the use of greases in
maintenance stock, consult your local supplier for evalua­tion. Refer to Table 1-3 in this Service Manual for an expla­nation of the lubricant key designations appearing in the
Lubrication Chart.

2.4 POSITIONING LIFT FOR ACCESS TO
COMPONENTS LOCATED UNDER THE
BASE FRAME

Access to the underside of the VP lift can be obtained by
lifting the machine with a fork lift truck, using the fork lift
pockets in the base frame.

Lifting with a Fork Truck (See Figure 2-1.)

1. Choose a fork lift truck capable of safely handling

the full weight of the machine.

2. Locate work area on a firm, level surface.

KEEP MACHINE LEVEL OR SLIGHTLY TILTED TOWARD FORKLIFT
TRUCK WHEN LIFTING TO PREVENT MACHINE FROM SLIDING
OFF LIFTING TINES.

3. When lifting with a fork truck, lift only using the fork
lift-truck pockets running the length of the machine’s
base frame from rear to front.

4. After lifting machine to desired work height, place
support stands under the machine. The support
stands must reach from the floor to the bottom of the
machine and be capable of safely handling the
weight of the machine.

LIFT USING ONLY THE
FORK LIFT POCKETS
RUNNING THE LENGTH
OF THE BASE FRAME

PLACE
SUPPORT
STAND
BETWEEN
MACHINE
AND
FLOOR

Figure 2-1. Accessing Machine Underside

Components by Lifting with a Fork Truck.

2-4 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

2.5 DRIVE MOTOR COMPONENT SERVICE
PROCEDURES

Torque Limiting Clutch Maintenance

VP Series machines are equipped with a torque limiting
clutch coupling on each drive axle. The clutch is mounted
inline on the drive axle between the drive wheel and the
drive motor gear box. The clutch is designed to slip at a
pre-set torque if the machines rear wheels are over-driven
while the machine is being towed, pushed or forklifted,
thus preventing damage to the drive gear box. Although
factory pre-set, the clutch assembly and torque should be
checked at the following interval:

• Every 3 months.

Visual Inspection and Limiting Torque
Checking Procedure

1. Locate the machine on a firm level surface.

KEEP MACHINE LEVEL OR SLIGHTLY TILTED TOWARD FORKLIFT
TRUCK WHEN LIFTING TO PREVENT MACHINE FROM SLIDING
OFF LIFTING TINES.

2. Carefully raise the lift to gain access to the under­side of the base frame. Refer to Section 2.4, "Posi­tioning Lift For Access to Components Located
Under the Base Frame".

3. Locate the clutch assembly on each rear drive axle
and check for the following;

a. Check the coupling chains for any loose or miss-

ing parts, i.e. pins, links, etc., replace if neces­sary.

b. Check that the allen-head set screws on the

(large) clutch adjusting nut are in place and
secure. Tighten or replace if necessary.

c. Check for any debris wedged in or wrapped

around the clutch coupling chains and axle
shafts. Remove debris and clean area if neces­sary.

Checking Clutch - Torque Setting (ft. lb.)

NOTE: Check that the machines brakes are engaged before

applying torque to the rear drive wheels.

1. Remove the drive wheels from the drive axles.

2. Select a torque wrench capable of setting a torque

of at least 185 ft. lb. Insert special tool (P/N-

0080229) into a 3/4" socket on the torque wrench.

3. Slide the tool onto the end of the drive axle aligning
the key on the axle shaft (install key on axle, if nec­essary), with key slot in the tool. (See Figure 2-2.)

4. Turn the torque wrench and note the torque setting
when the torque limiting clutch releases. The torque
(slip) setting should be set at 185 ft. lb. Check both
rear drive axles.

NOTE: The allowable breaking torque for the torque limiting

clutch can be set as much as 35 ft. lb. less than the
factory setting of 185 ft. lb., but never more than the
185 ft. lb. factory setting.

5. If torque setting is OK, re-install the wheels and
lower machine, IF NOT, see the following note.

NOTE: If torque setting is outside the allowable range of

specifications, the torque limiting clutch will need
adjustment. See Torque Limiting Clutch Adjustment
following.

SERVICE TOOL

P/N-0080229

(REQUIRES A 1-3/4” SOCKET)

TORQUE

LIMITING

CLUTCH

LOCATION

Figure 2-2. Check Torque Limit Clutch -

Torque Setting.

3120728 – JLG Lift – 2-5

SECTION 2 - SERVICE PROCEDURES

TORQUE LIMIT

CLUTCH

ADJUSTING NUT

ADJUSTING NUT

SET SCREWS

Torque Limiting Clutch Adjustment

NOTE: The large adjusting nut on the side of the clutch

assembly is a standard type thread.
If the torque (slip) setting of the clutch assembly is
under spec (by more than 35 ft. lb.), the large adjust­ing nut must be (tightened) turned clockwise to
increase the torque setting.
If the torque (slip) setting is over spec (over 185 ft.
lb.) the large adjusting nut must be (loosened),
turned counter-clockwise to decrease the torque set­ting.

1. Loosen the two (2) adjusting nut setscrews located
on the large adjusting nut on the clutch assembly.
(See Figure 2-3.)

2. Hold the drive axle steady using service tool (P/N-

0080229) and the torque wrench used to check the
torque setting.

3. Depending on how far off the original torque setting
was (see note at beginning of this procedure),
tighten or loosen the adjusting nut accordingly, then
recheck the (slip) torque setting.

4. When proper torque setting is achieved, re-tighten
the two (2) adjusting nut, setscrews.

5. Re-install the drive wheels, remove the jack stand
and lower the machine to ground.

Drive Motor Brake Adjustment/Removal

(See Figure 2-4. & Figure 2-5.)

Mounted onto the front of each drive motor housing is a
brake assembly. The brakes are normally ENGAGED
(brakes on) when the machine is parked and are
RELEASED electrically (brakes off) under normal driving
conditions, when the joystick is enabled and pushed in
any direction. The brakes can also be RELEASED manu­ally using the manual brake release lever mounted on the
side of the mast.

NOTE: The brakes are intended only as parking brakes to

keep the machine from moving while at rest. The
brakes are not used to stop the machine during driv­ing operations, this braking is controlled by the drive
motors themselves. Under normal driving conditions,
once released the brakes are not engaged again
until the machine comes to a complete stop.

MANUAL

BRAKE

RELEASE

ARM

LIMIT
(MICRO)
SWITCH

MAGNETIC

COIL

HOUSING

MOUNTING

PLATE

ARMATURE

PLATE

FRICTION

BRAKE

DISK

SPRINGS

SHIM WASHERS

Figure 2-3. Torque Limit Clutch -

Adjustment Components.

(AS REQUIRED)

SPACER

Figure 2-4. Brake Assembly Components

2-6 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

E

FRICTION BRAKE DISK FRICTION BRAKE DISK

ARMATURE PLATE ARMATURE PLATE

MAGNETIC COIL

(Not Energized)

MANUAL

RELEASE ARM/

ADJUSTMENT

SCREW

GAP SETTINGS - BRAKE ON

(Magnet Not Energized)

MOUNTING PLATE MOUNTING PLAT

0.006” GAP
BETWEEN

ARMATURE
PLATE AND

MAGNETIC COIL

0.020” GAP
UNDER

SCREW HEAD

BETWEEN

ARMATURE

PLATE

MAGNETIC COIL

(Energized)

MANUAL

RELEASE ARM/

ADJUSTMENT

SCREW

GAP SETTINGS - BRAKE RELEASED

Figure 2-5. Brake Armature Plate & Brake Disk Adjustment.

Operation (See Figure 2-4. & Figure 2-5.)

When the magnetic coil is not energized (brake on), the
armature plate is pushed away from the magnetic coil sur­face by heavy springs internally mounted in the magnetic
coil housing. This pressure forces the armature plate
against the friction brake disk holding it tight between the
armature plate and the mounting plate. The brake is not
released until either the magnetic coil is energized pulling
the armature plate away from the friction brake disk or the
brake is manually released using the manual brake
release handle.

A correctly adjusted brake will ideally have a measurment
of approximately .006" (but will operate normally at .004" to
.010") between the armature plate and magnetic coil
housing surface when the brakes are ENGAGED (brakes

3. With the brakes ENGAGED measure the air gap
between the armature plate and the magnetic coil
housing. The correct setting should be .006", how­ever the brakes will operate properly if the measure­ment is a minimum of .004" and a maximum of .010".
(See Figure 2-5.)

4. If the air gap falls outside the maximum allowable
setting of .010" the friction disk has worn. To correct
this replace the disk with a new one.

5. It the air gap is below the minimum allowable setting
of .004", recheck the areas between the magnetic
coil housing, armature plate, friction disk and
mounting plate for debris. Clean as neccessary. Also
check that the manual release arm screws are not
tightened to tight.

on).

Never allow any type of lubricant (oil, grease, hydraulic
fluid, etc.) to come in contact with the brake friction disk or
it’s contacting surfaces. Also if the brake becomes
clogged with debris or dirt the brake may not release
properly.

Manual Release Arm - Screw Adjustment

NOTE: Always check the armature plate gap setting is within

spec before attempting to adjust the manual release
arm screw adjustment.

1. With the brakes ENGAGED (brakes on) the air gap

Checking/Adjusting Armature Plate Gap Setting

1. First inspect that all parts of the brake assembly are

tight and secure. Tighten as necessary.

2. Inspect the brake for any debris which may be
lodged in the air gap between the armature plate
and magnetic coil when the brakes are ENGAGED
(brakes on); on either side of the friction disk when
the brake is RELEASED (brakes off); or any dirt or
debris lodged between the manual release arm and
the magnetic coil housing. Clean and remove debris
as necessary.

under the head of the manual release arm screw to
the surface of the armature plate should be set at
.020". Adjust using the locknut on the release arm
end of the screw.

2. With the brakes electrically RELEASED (brakes off)
the air gap under the screw head increases to
approximately .026" due to the armature plate move­ment towards the magnetic coil, releasing the fric­tion brake disk. When the brakes are RELEASED
(brakes off) manually the screw head pulls in against
the armature plate releasing the friction brake disk.

0.006” GAP
BETWEEN
FRICTION
DISK AND

ARMATURE

PLATE

0.026” GAP

UNDER

SCREW HEAD

BETWEEN

ARMATURE

PLATE

(Magnet Energized)

3120728 – JLG Lift – 2-7

SECTION 2 - SERVICE PROCEDURES

S

Brake Assembly Removal

1. Lift the machine to gain access to the underside

(See Section 2-4., "Positioning Lift For Access To
Components Located Under The Base Frame").

2. Disconnect the brake magnetic coil wiring connector
and the brake limit (micro) switch wiring connector
from their wiring harness connectors.

3. Disconnect the manual brake release cable from the
manual brake release arm attached to the brake
assembly.

4. Lower machine back down to ground level.

PLACE MACHINE ON A LEVEL SURFACE BEFORE BEFORE
REMOVING THE BRAKE ASSEMBLIES. MACHINE MAY ROLL
AWAY IF NOT SETTING ON A LEVEL SURFACE.

5. Using the Ground Control Switch, raise the platform
to gain access to the brake assemblies mounted on
the end of the drive motors located at the base of the
mast.

NEVER WORK UNDER AN ELEVATED PLATFORM UNTIL PLAT­FORM HAS BEEN SAFELY RESTRAINED FROM ANY MOVEMENT
BY BLOCKING OR OVERHEAD SLING.

6. Remove the four (4) hex cap screws securing the
brake assembly to the end of the drive motor and
remove the brake assembly from the end of the
drive motor.

6. Reconnect the manual release brake cable to the
manual release lever (Y shaped lever) and adjust
cable so brakes are released when manual release
lever is in the down position. (See Figure 2-6.)

MANUAL

RELEASE

BRAKE
CABLE

SET MANUAL

BRAKE RELEASE

HANDLE TO

FREE WHEELING
AND ADJUST HERE
UNTIL BRAKE DISK

IS COMPLETELY

RELEA

ED

TO MANUAL

RELEASE

BRAKE

HANDLE

MOUNTED

ON SIDE OF

MAST

BRAKES

ARE RELEASED

WHEN CABLE
PULLS LEVER

IN THIS DIRECTION

Figure 2-6. Manual Release Brake Cable Adjustment.

Brake Assembly Installation

1. Guide the manual release lever, brake coil and brake

limit switch wiring connectors through the opening
in the drive motor cover and base frame while slid­ing the brake assembly onto the front of the drive
motor. Engage the teeth of the disk brake with the
teeth on the drive motor brake gear.

2. If necessary, manually release the brake disk using
the manual release lever to allow the brake assem­bly to turn and align the four holes in the brake
mounting plate with the mating holes in the drive
motor end plate.

3. Secure the brake assembly to the drive motor using
four (4) hex cap screws with washers. Torque evenly
to 44 in. lbs.

4. Lift the machine to gain access to the underside
(See Section 2-4., "Positioning Lift For Access To
Components Located Under The Base Frame").

5. Reconnect the brake coil and brake limit switch wir­ing connectors to their respective wiring harness
connectors.

2-8 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

OTO

(2 EACH INSIDE FORK LIFT POCKET)

DRIVE MOTOR MOUNT

DRIVE MOTOR MOUNT

Drive Motor Removal

(See Figure 2-7.)

The VP drive motors consist of three sections, the gear
box atttached to the rear of the drive motor, the electric
drive motor itself, and the brake assembly mounded at the
front of the drive motor. Each drive motor is mounted inde­pendently of the other on a completely removable drive
assembly weldment at the back of the machine.

1. Disconnect the positive battery terminal from the left
side battery.

2. Remove the rear plate weldment from the machine,
(plate with the tie down lug) and set aside. Three (3)
bolts hold the top of the rear plate weldment to the
base frame, four (4) bolts attach it to the motor cover
weldment (located under machine) at the back and
on the sides.

3. Carefully raise the lift to gain access to the under­side of the base frame. Refer to Section 2.4, "Posi­tioning Lift For Access to Components Located
Under the Base Frame".

4. Remove the remaining two (2) bolts attaching the
motor cover to the base frame and set it aside.

DRIVE MOTOR/

BRAKE WIRING

CONNECTORS

DRIVE MOTOR

ASSEMBLY WELDMENT

5. Disconnect the wiring connectors to the drive motor

and the brake assembly on either or both sides,
depending on which drive assembly(ies) is being
removed.

6. Disconnect the manual release brake cable from the
brake assembly arm on either or both drive motors if
removing the complete drive assembly.

NOTE: If removing each drive motor seperately continue to

Step 7. If removing the complete drive assembly
with both motors attached go to Step 11.

7. Remove the one (1) bolt, nut, and two (2) washers
from the front of the drive motor mounting plate.

8. While holding the drive motor in place, remove the
remaining two (2) bolts with washers holding the
drive motor mounting plate to the drive motor
assembly weldment.

9. Slide the drive motor and torque limiting clutch
assembly towards the center of the machine, sliding
the torque limiting clutch off the outer drive shaft.

10. Move drive motor assembly and torque limiting
clutch to a suitable work bench for disassembly.

DRIVE M

ASSEMBLY

WELDMENT

ATTACH BOLTS

R

MANUAL

RELEASE

BRAKE
CABLE

DRIVE MOTOR

PLATE FASTENERS

(THREE ON EACH MOUNT

ALSO SEE INSET)

COVER

PLATE

REAR PLATE

WELDMENT

Figure 2-7. Drive Motor Assembly Removal.

3120728 – JLG Lift – 2-9

SECTION 2 - SERVICE PROCEDURES

Gear Box Disassembly/Assembly

IF REMOVING THE COMPLETE DRIVE ASSEMBLY, IT WEIGHS
APPROXIMATELY XX LB. AND WILL REQUIRE ASSISTANCE TO
LOWER. PREFERABLY USE A MOVABLE TRANSMISSSION OR
OTHER HYDRAULIC JACK TO CAREFULLY LOWER ASSEMBLY
FROM UNDER MACHINE.

11. Carefully remove the four (4) nuts and washers

(outer most holes on the drive assembly weldment)

from the carriage bolts attaching the drive motor
assembly to the base frame. Be aware of the weight

of the assembly before completely removing the fas­teners, see the CAUTION above.

12. Lower the drive assembly and place on a suitable
work surface.

(See Figure 2-8.)

The drive motor gear box is mounted on the rear of each
drive motor transferring power from the electric drive
motor to the rear drive wheels. It is a right angle worm
gear type box with a 50:1 reduction drive ratio. The inter­nal gears and bearings of the gear box are lubricated by
175cc’s of gear oil in an unvented aluminum alloy hous­ing. Early VP machines included a oil drain plug on the
rear surface of the gear box housing, later model
machines do not. The following procedures disassemble
and assemble the gear box housing internal components.

Gear Box Disassembly (See Figure 2-8.)

1. Remove the drive motor/gear box/brake assembly

from the machine using the procedure outlined pre­viously in this section of the manual.

Figure 2-8. Drive Motor Gear Box Assembly.

2-10 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

S

G

NOTE: The gear oil can be drained out when the side cover

is removed in the next step. Remove the side cover
from the gear box with the drive shaft side pointing
down, then tilt drive motor/gear box assembly to
drain the oil into a suitable container.

2. Remove the four (4) hex cap screws securing the
side cover to the gear box housing, and remove the
side cover and rubber seal ring. (Note: Early model

machines did not have the rubber seal ring and were
sealed with sealant only.) Be careful not to scratch or

gouge the mating surfaces between the cover and
the gear box housing. This area is sealed by the rub­ber ring/sealant and may leak oil if damaged.

3. Remove the wave washers from atop the large and
small bearings and lay inside their respective holes
in the side cover.

4. Using a suitable catch container, drain the gear oil
from the gear box housing.

5. Remove the drive shaft assembly from the housing.
Place the drive motor/gear box assembly on a
hydraulic press with the open side of the gear box
housing facing down. Support the gear box housing
surface but do not block the free travel of the drive
gear and bearings, on the drive shaft or the pinion
gear assembly.

6. With the open surface of the housing properly sup­ported, carefully press the drive shaft down through
until it is free of the housing. When the drive shaft
assembly is free, slide it completely out of the hous­ing.

7. To remove the large (47mm) (cover side) bearing
and (housing side) bearing from the drive shaft, use
a suitable hydraulic press and press the bearing(s)
off the shaft. Keep the spacer from between the
cover side bearing and the drive shaft gear for reuse
during assembly.

8. To remove the small (32mm) bearing(s) from the
gear (brass) and pinion assembly, use a suitable
hydrauic press and press the bearing(s) off the gear
and pinion shaft.

9. To remove the (brass) worm gear from the pinion
assembly, use a suitable hydraulic press and press
the gear off the pinion shaft. Keep the (brass) gear
key for reuse during assembly.

10. Inspect the drive shaft seal for cuts, cracks and
wear, or if showing signs of leakage. Replace if nec­essary.

Gear/Pinion Shaft Assembly (See Figure 2-9.)

1. Locate the pinion gear/shaft, place the key for the

(brass) worm gear into the slot on the gear shaft.

2. Press the (brass) worm gear onto the pinion shaft
and align the keyway in the (brass) worm gear with
the key on the pinion shaft. Press the (brass) worm
gear onto the shaft until it bottoms out against the
pinion gear teeth.

NOTE: Press bearings onto the shaft pressing only against

the bearing inner race. Do not press against the
outer race or damage could occur to the bearing.

3. Press the small (32mm) bearings onto the ends of
the pinion shaft. The inner race of the bearing on the
pinion gear side can be bottomed out against the
pinion gear. Do not press the bearing on the (brass)
worm gear side of the shaft in tight against the
(brass) worm gear. This bearing must be flush with
the end of the shaft on the outside, yet have clear­ance from the (brass) worm gear on the inside, so it
can rotate freely.

Drive Shaft Assembly (See Figure 2-10.)

1. Slide the (housing side), 42mm x 25mm x 12mm

(thinner) bearing onto the long end of the drive shaft.
Press the bearing inner race until it bottoms against
the shaft shoulder between the drive gear and the
bearing.

2. Slide the narrow spacer onto the drive gear end of
the shaft and press the (cover side) 42mm x 20mm x
14mm (wider) bearing onto the drive shaft until it
bottoms against the spacer. This bearing should be
flush with the end of the drive shaft.

IDE PROFILE

32mm

BEARING

WORM

GEAR

(BRASS)

PINION GEAR/

SHAFT

LEAVE

GAP HERE

32mm

BEARIN

WORM GEAR

KEY

Figure 2-9. Gear/Pinion Shaft Assembly.

3120728 – JLG Lift – 2-11

SECTION 2 - SERVICE PROCEDURES

O

G

Final Gear Box Assembly

1. If necessary, install a new drive shaft lip seal into the

drive shaft hole in the gear box housing before
assembling the drive shaft gear set into the gear
box. Install the seal so it is even with the bottom of
the chamfer in the drive shaft hole on the outside of
the housing and flush with the bearing seat on the
inside of the housing.

2. Lube the drive shaft seal with a thin film of oil before
sliding the drive shaft over the seal.

3. Position the gear box with open cover side up, allow
space under the gear box for the drive shaft to
extend through without obstruction.

4. Hold the gear and pinion, and drive shaft assembies
together with the pinion gear and the ring gear on
the drive shaft meshing. Now carefully slide these
assemblies into the gear box housing sliding the
drive shaft through the drive shaft lip seal.

NOTE: While assembling the gear assemblies into the gear

box housing, be careful with the drive shaft seal and
the softer brass worm gear and brass drive worm
gear from the drive motor.

5. Continue to drop the gear assemblies into the gear
box, align the bearings with the bearing seats in the
housing on both assemblies. Drop the gear and pin­ion (smaller) bearing into it’s seat first, while wiggling

that gear set align the drive shaft bearing and wiggle
it into it’s seat. When both are seated continue to
next step.

6. With the gear box still positoned with the open cover
side up, fill the gear box with six (6) ounces (U.S.)
(175cc’s) of good quality worm gear oil (Specifica-
tion - SAE 90 weight - AGMA#5 - EP Compounded).
When pouring the gear oil, wet the gears and bear­ings with the oil.

7. Wet with gear oil and place the large wave washer
on the end of the drive shaft bearing and the small
wave washer on the end of the gear and pinion bear­ing.

8. Clean the mating surfaces of the side cover and the
gear box and check that the cover dow guide pins
are properly installed in the cover.

9. On older model gear boxes apply sealant to the
cover mating surface on the gear box. On newer
model gear boxes insert the rubber seal into the
groove in the cover.

10. Using the cover dow guide pins, place the cover
onto the gear box housing.

11. Secure using the four (4) hex cap screws, torque
screws evenly to 90 in. lbs.

12. Install the drive motor back onto the machine.

N

PINI

GEAR

SPACER

PINION GEAR KEY

42mm x 25mm x 12mm

BEARING

DRIVE SHAFT

SIDE PROFILE

42mm x 20mm x 14mm

BEARIN

Figure 2-10. Drive Shaft Assembly.

2-12 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

SPRING BRACKET

Drive Motor Brush Replacement

Each drive motor contains two (2) brushes, the brushes
are located under the two (2) large round slotted brush
caps on the front end of each drive motor.

BRUSH CAP

DRIVE MOTOR

BRUSH

ASSEMBLIES

LOCATED

INSIDE

HERE

BRUSH CAP

BRAKE

ASSEMBLY

Figure 2-11. Drive Motor Brush Location.

Brush Removal (See Figure 2-12.)

Removal of the brushes also requires the removal of the
drive motor(s) from the machine, see procedure
described earlier in this section for instructions to remove
the drive motors. If not already done, disconnect the posi­tive (+) battery cable from the left side battery before pro­ceding.

1. Unscrew the large round brush caps from each side
of the drive motor, use as large a screw driver as
possible.

2. The brushes are retained by constant-force, roll-type
springs. To remove the springs, press inward on the
end of the spring retaining bracket using the tip of a
pair of long nose pliers or other appropriate tool.
The brushes should pop out, if not, they can be
removed by pulling outward on the spring brackets
with a pair of long nose pliers after the inside ends
are unhooked.

3. Now pull the brush out of the brush box by it’s wire
(pig-tail).

NOTE: If only inspecting the brushes, it is not necessary to

remove the pig-tail terminal from it’s connection to
the brush box.

4. Loosen the the screw securing the pig-tail terminal
end to the brush box and slide the terminal end out
from under the screw completely removing the
brush from the drive motor.

DISCONNECT THE POWER LEADS FROM THE POWER SOURCE
BEFORE INSPECTING OR REPLACING BRUSHES.

Brush Cleaning and Inspection

Brush wear rate varies depending on the individual appli­cation’s duty cycle, and should be inspected at frequent
intervals to determine an appropriate inspection schedule.
Brushes should be replaced before they are less than .375
in. (9.5mm) in length. Carbon dust accumulation should
be removed periodically. If the end shield has been
removed from the drive, a clean, dry, non-linting cloth can
be used for cleaning. DO NOT use solvents as they my
damage non-metallic parts and adversely affect subse­quent brush commutation.

SPRING BRACKET

SPRING

BRACKET

HOOKS

BRUSH

PIGTAIL WIRE

Figure 2-12. Drive Motor Brush Installation.

BRUSH BOX

BRUSH BOX

INSULATOR

3120728 – JLG Lift – 2-13

SECTION 2 - SERVICE PROCEDURES

CO

Brush Reassembly (See Figure 2-12.)

MAKE CERTAIN THAT THE GROUND WIRE IS SECURELY RECON­NECTED TO THE GROUND TERMINAL IF REMOVED. LEADS,
INTERNAL TO THE SHEILD, MUST BE ROUTED AWAY FROM THE
ARMATURE, (E.G.: BE CLOSE TO THE INSIDE WALL OF THE
ALUMINUM SHIELD) TO PREVENT A SAFETY HAZARD AND/OR
DAMAGE TO THE MOTOR.

CORRECT

1. Install the brush (pig-tail) terminal end under the

screw on the brush box in the same manner as the
old brush that was removed and tighten the screw.

2. Slide the body of the brush into the brush box, be
certain that the wire (pig-tail) is aligned with the slot
in the base of the brush box so that it can "feed" into
the brush box slot as the brush wears down.

NOTE: The pig-tail wire should be formed to rest against the

nonmetallic insulator. It must be spaced from any
metallic surfaces other than the brush box by a mini­mum of .125 in. (3mm).

3. Now install the brush retaining spring bracket. Grasp
the tip of the spring bracket such that the roll-type
spring will be on the "brush side" of the brush box,
and resting on top of the brush when the brush
spring is completely installed.

4. Push the spring bracket slowly into it’s slot while let-
ting it’s two attaching hooks slide on the wall of the
brush box.

5. Stop, but do not release the spring bracket when it’s
hooks slip around the edge of the brush box.

6. While still grasping the spring bracket with the pliers,
slowly bring the spring back out of the brush box
until the hooks latch around the edge of the brush
box.

7. Now release the spring bracket and check that it is
lying flat against the brush box wall. If it is "cocked" it
is improperly seated and will have to be reinstalled.

RRECT

IN

Figure 2-13. Correct/Incorrect Brush Spring Bracket

Positions.

THE SPRING BRACKET MUST BE ALSO LIE COMPLETELY INSIDE
THE BRUSH BOX AND NOT OUT OVER THE EDGE. THE ROLL
END OF THE SPRING MUST BE CENTERED ON THE TOP OF THE
BRUSH. (SEE FIGURE 2-13.)

8. Also apply slight pressure by pulling up on the
spring bracket to be certain it is hooked securely
around the brush box wall at the bottom of the brush
box.

9. Screw the brush caps back into the end shield using
the largest possible screwdriver.

10. Reinstall the drive motor(s) to the machine and
reconnect the power source.

NEW BRUSHES MAY BE SEATED BY RUNNING THE DRIVE
MOTOR AT NO LOAD. PROPER SEATING IS REQUIRED FOR
LOWEST BRUSH NOISE LEVEL.

2-14 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

2.6 PLATFORM CONTROL BOX SERVICE
PROCEDURES

Joystick Calibration Procedure

1. Turn off all power to the platform control.

2. Move the joystick to the maximum forward position

and hold it there.

NOTE: Joystick will be held in the maximum forward position

until asked to release it in Step 5.

JOYSTICK ASSEMBLY

S/N- 02996 TO PRESENT

(INCLUDES DRIVE ENABLE BUTTON)

TOUCH PAD

UPPER

HOUSING

INTREGRATED

CIRCUIT

BOARD

SWITCH

3. Turn on power to the platform control, nine (9) LED’s

will flash rapidly on the platform control touch pad.

4. Depress the horn switch pad, the alarm will sound
for about one (1) second, then release the horn pad.

5. Now release the joystick to the neutral position.

6. Turn off system power.

The joystick calibration is now complete.

JOYSTICK

ASSEMBLY

PRIOR TO

S/N- 02996

(USED THE

TOUCH PAD

ENABLE

SWITCH)

LOWER

HOUSING

SPEED

CONTROL

KNOB

EMERGENCY

STOP SWITCH

BUTTON

SPEED

CONTROL

SWITCH

EMERGENCY

STOP SWITCH

Figure 2-14. Platform Control Box Assembly (Exploded View)

3120728 – JLG Lift – 2-15

SECTION 2 - SERVICE PROCEDURES

Platform Control Box Disassembly

DO NOT ATTEMPT TO DISASSEMBLE THE PLATFORM CONTROL
BOX IF MACHINE IS STILL UNDER WARRANTY. OPENING THE
PLATFORM CONTROL BOX WHILE THE MACHINE IS UNDER
WARRANTY WILL VOID THE WARRANTY. IF UNDER WARRANTY
REQUEST A REPLACEMENT BOX FROM THE FACTORY.

The VP Series platform control box allows for replacement
of five (5) components internal to the box.

• Controller Integrated Circuit Board

• Joystick Assembly

• Emergency Stop Switch

• Speed Control Switch

• Touch Pad Switch Assembly

Except for the touch pad switch assembly, which plugs
into the circuit board, replacement of each component
requires unsoldering, then soldering each replacement
components’ wiring to the controller’s integrated circuit
board. Due to the small contact area when connecting
each wire to the circuit board this soldering requires pre­cise temperatures and neatness of the soldered point
itself so as not to destroy the circuit board or cross any of
the circuit paths on the board.

Lower Half Of Housing Removal

1. Position the control box upside down and remove

the six (6) screws attaching the lower half of the
housing to the upper half of the control box housing.

2. Lay screws and lower housing aside.

Joystick Assembly Removal

NOTE: To completely remove the joystick assembly, its wir-

ing will need to be unsoldered from the intregrated
circuit board.

ELECTROSTATIC DISCHARGE CAN DAMAGE COMPONENTS ON
THE INTEGRATED CIRCUIT BOARD. PLACE THE PLATFORM
CONTROL BOX ON A NON-CONDUCTIVE SURFACE WHEN OPEN­ING THE BOX AND WORKING DIRECTLY WITH THE CIRCUIT
BOARD.

Removing Control Box From Platform

1. Turn off all power to the platfom control box.

2. Unhook the wiring harness cable at the quick-dis-

connect coupling. (Early VP models were not
equipped with the quick-disconnect coupling, skip to
Step 4.)

3. Remove the platform control box and box mount to
a suitable work surface.

4. Remove the control box from the control box mount
by removing the four (4) nuts from the studs on the
bottom of the control box.

5. Unplug the wiring harness cable connector on the
back of the lower housing half.

6. Lay control box mount and wiring harness assembly
aside.

1. Remove the four (4) screws from the top of the bezel
around the base of the joystick and slide the joystick
assembly out of the upper housing.

2. Unplug the touchpad switch ribbon connector from
the circuit board connector socket.

2-16 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

3. Remove the four (4) screws attaching the circuit
board to the upper housing.

NOTE: If reusing the circuit board be careful when unsolder-

ing component wires DO NOT OVERHEAT BOARD.

4. Position the circuit board and unsolder the wires
from the joystick assembly at the J2, J3 and J7 loca­tions on the circuit board. (See Figure 2-15.)

NOTE: (VP model joystick assemblies prior to S/N- 02996

did not have the drive enable button on the joystick
knob. Wires from this design were attached in the J3
location on the circuit board only.)

5. With all the joystick wiring unsoldered remove joy­stick assembly from the control box.

Emergency Stop Switch Removal

1. Remove the switch part of the emergency stop

switch by carefully prying upward at the corner of
the switch using a straight blade screwdriver. This
will seperate the switch from the reset button part of
the emergency stop button assembly.

2. Position the circuit board and locate the emergency
stop switch wires connected at locations J8, J9, J10
and J11. Unsolder the four (4) wires to the switch to
remove the switch from the board. (See Figure 2-15.)

J2 - J7

JOYSTICK

WIRING

(2 WIRES)

(Later Models With

Enable Button On

Knob Only)

J8 - J9

J10 - J11

EMERGENCY

STOP

SWITCH

(4 WIRES)

TOUCHPAD

SWITCH

CONNECTOR

SOCKET

Figure 2-15. Platform Control - Circuit Board Component Wiring Connections.

J3

JOYSTICK

WIRING

(5 WIRES)

J5

SPEED

CONTROL

SWITCH

(3 WIRES)

3120728 – JLG Lift – 2-17

SECTION 2 - SERVICE PROCEDURES

WIRES FROM JOYSTICK

3. Remove the reset button part of the emergency stop

switch by unscrewing the collar on the inside end of
the reset button assembly.

Speed Control Switch Removal

1. Remove the speed control knob by pulling up on the

knob until it is free of the switch shaft.

2. Loosen and remove the retaining nut and lock
washer from the switch collar and pull the switch out
of the housing.

To u c h Pa d Sw i t c h R e m o v a l

1. Unplug the touch pad ribbon cable connector from

the circuit board connector socket. (See Figure 2-

15.)

2. Using a thin tool, start by lifting an edge of the touch
pad switch and slowly peel away it from the face of
the upper housing until completely free.

Platform Control Box Assembly

To assemble the components back into the control box
follow the previously outlined disassembly procedure and
reverse the steps for the component being installed. The
following are additional guidelines for assembling each
component.

NOTE: Be careful when soldering component wires to the

circuit board DO NOT OVERHEAT BOARD.

Joystick Installation

1. Use the following illustrations to reattach the wires

from the joystick to the circuit board.

3. Position the circuit board and locate the speed con­trol switch wires connected at location J5. (See Fig-
ure 2-15.) Unsolder the three (3) wires to the switch
to remove the switch from the platform box.

CIRCUIT BOARD

COMPONENT SIDE

YELLOW
BLUE
BLACK
RED
WHITE

J3

CONTROL

2-18 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

)

ORANGE

WHITE W/ORG

CIRCUIT BOARD

COMPONENT SIDE

WIRES FROM SPEED

Speed Control Switch Installation

1. Use the following illustrations to reattach the wires

from the speed control switch to the circuit board.

WIRES

WHITE (light gauge)

FROM
JOYSTICK
CONTROL

(Later Model

Joystick

w/Drive

Enable

on Knob)

2. If damaged replace the gasket between upper hous­ing surface and the joystick mounting surface before
assembling.

YELLOW (light guage

CIRCUIT BOARD

COMPONENT SIDE

Emergency Stop Switch Installation

1. Use the following illustration to reattach the wires

from the emergency stop switch to the circuit board.

GREEN

J5

CONTROL SWITCH

Touch Pad Switch Installation

1. Thoroughly clean the surface of the upper housing

where the touch pad switch adheres to the upper
housing.

2. Remove all traces of silicone sealant from around
the slot where the ribbon cable connector passes
through the housing.

CIRCUIT

BOARD

COMPONENT

SIDE

2. If damaged replace the gasket between the stop

switch base plate and the upper housing mounting
surface.

RED (PIN 21)
BLACK (PIN 13)
BLACK (PIN 14)
RED (PIN 22)

WIRES FROM

EMERGENCY

STOP SWITCH

APPLY SILICONE

SEALANT HERE

IN THIS SLOT

3. Remove the adhesive backing off the new touch pad

switch, keep this surface clean and free of debris
during assembly.

4. Assemble the new touch pad switch to the upper
housing surface by first sliding the ribbon cable con-

3120728 – JLG Lift – 2-19

SECTION 2 - SERVICE PROCEDURES

nector from the touch pad switch through the slot at
the top of the housing. Before pressing the touch
pad adhesive side to the upper housing mounting
surface, visually align the touch pad edges with the
edges of the recess in the housing mounting sur­face.

5. Once the touch pad is installed, on the underside of
the housing apply just enough silicone sealant to fill
the small slot around the ribbon cable to help seal
the slot and also strengthen the ribbon cable con­nection at the touch pad surface.

6. Re-install the circuit board and plug the ribbon cable
connector into the circuit board cable socket.

Lower Half Housing Installation

1. Before installing the lower half housing apply a non-

conductive grease to the square holes of the wiring
harness connector socket on the inside of the hous­ing socket. This will help keep out dirt and moisture.

WIRING HARNESS

CONNECTOR SOCKET

2.7 BATTERY CHARGER ASSEMBLY AND
DISASSEMBLY

General Information

DO NOT ATTEMPT TO DISASSEMBLE THE BATTERY CHARGER
IF MACHINE IS STILL UNDER WARRANTY. OPENING THE BAT­TERY CHARGER WHILE THE MACHINE IS UNDER WARRANTY
WILL VOID THE CHARGER WARRANTY. IF UNDER WARRANTY
REQUEST A REPLACEMENT CHARGER FROM THE FACTORY.

ALSO BEFORE REPLACING ANY COMPONENT, USE THE
CHARGER MANUFACTURERS TROUBLESHOOTING GUIDE
INCLUDED WITH THE MACHINE FOR CHECKING THE INTERNAL
AC AND DC CIRCUITS TO DETERMINE WHICH COMPONENT HAS
FAILED. COMPLETE WIRING DIAGRAMS PERTAINING TO YOUR
MODEL CHARGER ARE ALSO INCLUDED IN THE MANUFACTUR­ERS CHARGER MANUAL.

The VP Series battery charger allows for replacement of
the following internal components. Consult your Illustrated
Parts Manual for part numbers of these components
which are available from the JLG Parts Department:

• Transformer

• Printed Circuit Board

2. Carefully slide the lower housing onto the upper half
of the platform control box assembly until seated
completely against the upper housing edges.

3. Secure lower half housing to the upper half housing
using the six (6) screws removed during dissassem­bly.

• Shunt Assembly

• Interlock Relay

• SCR Rectifier

• AC Circuit Breaker

• DC Circuit Breaker

Replacement and troubleshooting of these components
requires removal of the battery charger from it’s mounting
position on the machine.

Battery Charger Removal

1. Remove the rear cover from the machine.

2. Unbolt and lower the MC-1 Controller Box.

3. Remove the four (4) capscrews securing the charger

to it’s mounting plate.

4. Disconnect the DC wiring from the positive/negative
battery terminals and interlock connector from the
wiring harness.

5. Remove the charger from the machine.

2-20 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

Battery Charger Part Replacement

Cover Removal

1. Remove the eight (8) screws on the sides of the

charger cover and remove cover.

Tran s fo r mer R epl ace m ent

1. Disconnect the wiring connecting the the trans-

former to other components within the charger
assembly.

2. Remove the four nuts from the cap screws securing
the transfromer brackets to the base of the charger
chassis.

3. Remove transformer.

Printed Circuit Board Replacement

1. Disconnect the wide wiring connector from the end

of the circuit board.

2. Remove the four (4) screw attaching the card to the
front face of the charger chassis.

3. Remove the circuit board.

Shunt Assembly Replacement

1. Carefully remove the screw from each end of the

shunt assembly. The white insulator may need to be
restrained to keep it from turning while removing the
shunt assembly fasteners. Also make note of the
position of each washer, nut and wire connector
when removing for later assembly.

3120728 – JLG Lift – 2-21

SECTION 2 - SERVICE PROCEDURES

Interlock Relay Replacement

1. Disconnect the wiring connected to the relay.

2. Remove the two (2) nuts securing the interlock relay

to the chassis base.

3. Remove the relay.

SCR Rectifier Replacement (Either Side)

1. Remove the wiring from the SCR Rectifier.

2. Remove the nut securing the rectifier to the insulated

aluminum chassis bracket.

3. Remove the SCR Rectifier.

AC Circuit Breaker Replacement

1. Disconnect wiring connected to the breaker poles.

2. Remove the two (2) nuts securing the AC breaker to

the chassis screws.

3. Remove the breaker from the chassis.

DC Circuit Breaker Replacement

1. Remove the wiring from the DC breaker terminals.

2. To remove the breaker from the front face of the

charger, on the inside of the charger front face, push
in on the tabs located on the sides of the breaker
assembly and remove the breaker out the front of
the charger.

LOCKING

TABS

2-22 – JLG Lift – 3120728

2.8 HYDRAULIC LIFT CYLINDER -

AVOID DAMAGE TO

S

REMOVAL, INSPECTION AND REBUILD

HYDRAULIC CYLINDERS ARE DESIGNED TO HOLD HYDRAULIC
FLUID UNDER HIGH PRESSURE. BE SURE ALL APPROPRIATE
MEASURES ARE TAKEN TO RELIEVE RESIDUAL PRESSURE IN
THE CYLINDER BEFORE DISCONNECTING LINES.

Lift Cylinder Removal

Removal of the hydraulic lift cylinder without removing the
mast from the machine requires laying the machine on it’s
back (hood side) with the platform end on top.

1. Remove the hood from the rear of the machine.

2. Disconnect and remove the batteries from the

machine, to prevent acid leakage.

3. Seal the vented cap on the hydraulic fluid reservoir
by removing the cap, covering the hole with a few
layers of plastic wrap or equivalent, then install and
tighten the cap over the plastic wrap.

SECTION 2 - SERVICE PROCEDURES

SUPPORT

CONTROLS IN

THI

AREA

Figure 2-16. Machine Positioned for Cylinder

Removal.

MAST

NOTE: If a quick-change platform is attached to the machine

remove the platform to help reduce the weight of the
machine during machine lay back.

4. Use a forklift truck or overhead crane and carefully
lay the machine on it’s back, place a support under
the mast end. (See Figure 2-16.)

5. Manually extend the mast assembly approximately
two (2) feet, to allow access to the sheave wheel­anchor block at the top of mast section-2.

6. Remove the set screw securing the lift cylinder rod
to the sheave wheel anchor block at the top of mast
section-2.

7. Under the base assembly remove the four (4) bolts
attaching the PHP bar actuator assembly to the lift
cylinder mount. Secure the assembly out of the way.

8. Carefully disconnect and cap the extend and return
lines and fittings from the lift cylinder, drain any
hydraulic fluid into a container.

9. Remove the bolt securing the lift cylinder to the cyl­inder mount.

10. Remove the four (4) bolts, washers and nuts attach­ing the cylinder mount to the base frame. Remove
the mount and lay aside.

11. At the bottom of mast section 2, slide the lift cylinder
assembly out and place on a suitable work surface.

Cylinder Disassembly

1. Before disassembling the cylinder, clean away all

dirt and foreign substances from openings, particu­larly the head area.

NOTE: Always protect the chrome surface of the cylinder

rod during assembly and disassembly. Any damage
to this surface will require replacement of the rod.

2. Extend the rod until the piston bottoms out against
the cylinder head.

3. Compress the head retraining ring enough to allow
the the cylinder head to be removed.

4. Carefully slide the head/rod/piston assembly out of
the cylinder tube. A gentle tap on the head assembly
may be required to remove the head from the cylin­der tube.

5. Place the head/rod/piston assembly on a surface
that will not damage the chrome.

6. Remove the piston locknut and separate the piston
from the rod.

7. Slide the head off the rod from the piston end.

NOTE: When removing the old seals use only blunt tools, be

sure there are no sharp edges that may damage the
seal grooves during removal. Scratching the groove
may cause by-pass.

8. Remove and discard all old seals.

3120728 – JLG Lift – 2-23

SECTION 2 - SERVICE PROCEDURES

Lift Cylinder Component Inspection

Cylinder Rod

There should be no scratches or pits deep enough to
catch the fingernail. Pits that go to the base metal are
unacceptable. Scratches that catch the fingernail but are
not to the base metal, less than 0.5 inch long and primarily
in the circumferential direction are acceptable provided
they cannot cut the rod seal. Chrome should be present
over the entire surface of the rod and the lack thereof is
unacceptable. In the event that an unacceptable condition
occurs, the rod should be repaired or replaced.

Cylinder Head

Visually inspect the inside bore for scratches or polishing.
Deep scratches are unacceptable. Polishing indicates
uneven loading and when this occurs, the bore should be
checked for out-of-roundness. If out-of-roundness exceed

0.007", this is unacceptable. Check the condition of the
dynamic seals (wiper, rod seals) looking particulary for
metallic particles embedded in the seal surface. It is nor­mal to cut the static seal on the retaining ring groove upon
disassembly. Remove the rod seal, static o-ring and
backup and rod wiper. Damage to the seal grooves, par­ticularly on the sealing surfaces, is unacceptable. In the
event that an unacceptable condition occurs, the head
should be replaced.

Piston

Visually inspect the outside surface for scratches or pol­ishing. Deep scratches are unacceptable. Polishing indi­cates uneven loading and when this occurs, the diameter
should be checked for out-of-roundness. If out-of-round­ness exceeds 0.007", this is unacceptable. Check the con­dition of the dynamic seals and bearings looking
particularly for metallic particles embedded in the bearing
and in the piston seal surface. Remove the seals and
bearings. Damage to the seal grooves, particularly on the
sealing surfaces, is unacceptable. In the event that an
unacceptable condition occurs, the piston should be
replaced.

Tube Ass e mb l y

Visually inspect the inside bore for scratches and pits.
There should be no scratches or pits deep enough to
catch the fingernail. Scratches that catch the fingernail but
are less than 0.5 inch long and primarily in the circumfer­ential direction are acceptable provided they cannot cut
the piston seal. The roughness of the bore should be
between 10 and 20 µ inches RMS. Significant variation
(greater than 8 µ inches difference) are unacceptable. In
the event that an unacceptable condition occurs, the tube
assembly should be repaired or replaced.

Cylinder Assembly

(See Figure 2-17.)

1. Rinse the inside of the tube with hydraulic fluid and
allow to drain. A high-pressure rinse followed by a
wipe with a lint-free rag is preferable. Clean all inter­nal components of any foreign material.

2. Lubricate the head and all seals with hydraulic fluid
prior to installation. Install the seal, wiper, o-ring,
back-up ring, and retraining ring to the cylinder
head.

3. Lubricate the piston and all components with
hydraulic fluid. Install the seal and wear ring to the
piston.

NOTE: Re-check that seals are not twisted or pinched and

are properly seated.

4. Place the rod on a clean table. Install the static o­ring seal into the groove on the piston end of the
rod.

5. Install the head followed by the piston onto the rod
noting the proper orientation of each component.
Torque the piston nut to 175-200 ft. lbs.

6. When the rod assembly is ready to be installed into
the tube, liberally apply an anti-seize lubricant to the
head outer surface, especially the static seal.

7. Next dip the entire rod assembly into hydraulic fluid
and stuff this assembly into the tube. Watch the
seals as they pass over the rod port (if visible) to be
sure they are not nicked or cut.

8. Install the head until the retaining ring seats in it’s
groove.

Cylinder Installation

To install the lift cylinder reverse the Lift Cylinder Removal
instructions at the start of this section, however perform
the following additional steps during re-assembly.

1. Apply Loctite #222 (purple) to the setscrew securing
the lift cylinder rod to the sheave wheel anchor block
at the top of mast section-2.

2. Torque the four (4) cylinder lift mounting bolts to 34
ft. lb.

2-24 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

LOCKNUT

(Torque

S

RETAINING RING

GROOVE

CYLINDER

TUBE

ASSEMBLY

WEAR

RING

PISTON

SEAL

O-RING

O-RING

BACKUP

RING

CYLINDER

HEAD

RETAINING

RING

ROD

SEAL

ROD

WIPER

175-200 Ft. Lb.)

PISTON

WHEN ASSEMBLING

CYLINDER

APPLY ANTI-SEIZE

COMPOUND
AROUND THE HEAD
IN THI

AREA ONLY

CYLINDER

HEAD

Figure 2-17. Lift Cylinder Internal Component Assembly Cross-Section.

CYLINDER

ROD

3120728 – JLG Lift – 2-25

SECTION 2 - SERVICE PROCEDURES

2.9 MAST ASSEMBLY AND DISASSEMBLY
PROCEDURES

The VP Series personnel lift mast sections are contructed
of extruded aluminum, protected with an anodized surface
finish. The mast sections are interlocked into each other
when assembled, by internally mounted slide pads at the
top and bottom of each mast section. These slide pads
run up and down in slide pad channels on each side of
the mast.

Each VP model mast assembly contains a different num­ber of mast sections as shown following;

Table 2-2. VP Series Mast Component Features

Model

No. of Mast

Sections

10VP 3 Cable

15VP 4 Cable

20VP 5 Chain & Cabl e

Assembly procedures for all mast sections is basically the
same, carefully slide the mast sections together from bot­tom until mast ends are even. (When sliding the mast sec­tions together, be careful not to scratch the anodized
surface). Assemble the hardware to the bottom of mast
section first, slide this section out the top of previous sec­tion and assemble hardware to the top of mast, (See Fig-
ure 2-1.). Always install slide pad shims with slide pads
inserted into the slide pad channels, (ends of mast sec-

Extend/Retract

Device

tions even). Applying silicone spray onto the slide pads
and slide pad channels before assembly will help mast
sections slide easier after slide pads have been properly
shimmed.

Mast Disassembly Procedure

NOTE: Reference to mast sections-3/-4/-5 (platform mount-

ing section) depends on which VP model lift you are
working on.

1. After the mast assembly has been removed from the
machine, lay the mast assembly down on a suitable
work table with the platform mounting section on
top, facing up.

2. Remove the sequencing cables and hardware from
the sides of the mast assembly. Also remove the
cover from the top of the mast assembly.

3. Remove cable adjust nuts from threaded ends of
cable attached to the cable anchor plate on BOT­TOM end of mast section-3/-4/-5 (platform mounting
section). Push threaded ends of cable through
anchor plate.

4. At the TOP of mast section—3/-4/-5, pull cables out
and allow to hang loose.

NOTE: When sliding mast sections apart, be careful not to

scratch or score the anodized surface in the slide
pad channels.

OPEN RAIL

(REFERS TO OPEN RAIL

FRONT OF MAST SECTION)

CLOSED RAIL

(REFERS TO CLOSED RAIL

BACK OF MAST SECTION)

TOP

(REFERS TO TOP END

OF MAST SECTION

WHERE COVER AND

SHEAVE WHEELS

ARE ATTACHED)

BOTTOM

(REFERS TO BOTTOM END OF

MAST SECTION WHICH SETS IN

MACHINE’S BASE FRAME)

Figure 2-18. Mast Section - Assembly Reference.

2-26 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

5. Carefully slide mast section-3/-4/-5 out BOTTOM of
mast section-2/-3/-4 rails. Disassemble slide pads,
shims and cable anchor plate from mast section-3/­4/-5, if necessary.

NOTE: Steps 6 through 10 apply to removal of mast section-

4 on model 20VP lifts which have five (5) mast sec­tions. If servicing a 15VP mast, go to step 11, or a
10VP go to step 17.

6. Remove cable adjust nuts from threaded ends of
cables attached to the cable anchor plate on bottom
end of mast section-4. Push threaded ends of
cables through anchor plate.

7. At top of mast section-4, pull cables out and allow to
hang loose.

8. Slide mast section-4 out the TOP of mast section-3
far enough to allow access to the cable sheave
wheel assembly.

9. Remove countersunk-flathead screws securing
cable sheave wheel assembly attach bars on both
side rails at top of mast section-4 and remove
sheave wheel assembly.

NOTE: When sliding mast sections apart, be careful not to

scratch or score the anodized finish in the slide pad
channels.

10. Carefully slide mast section-4 out BOTTOM of sec­tion-3. Remove slide pads, shims and cable anchor
plate, if necessary.

NOTE: Steps 11 through 16 apply to removal of mast sec-

tion-3 on 15VP (cable actuated) & 20VP (cable/chain
actuated) lifts. If servicing a 10VP mast, go to step

17.

11. Remove cable/chain adjust nuts from threaded ends
of cable/chain attached to the cable/chain anchor
plate on BOTTOM end of mast section-3. Push
threaded ends of cable/chain through anchor plate.

12. At TOP of mast section-3, pull cables/chains out and
allow to hang loose, (be certain floor surface is clean

and free of any metal chips or debris which may stick
to lubricated chains).

13. Slide mast section-3 out TOP of mast section-2 far
enough to allow access to the cable/chain sheave
wheel assembly.

14. Remove countersunk-flathead screws securing
cable/chain sheave wheel assembly attach bars on
both side rails at TOP of mast section-3 and remove
the sheave wheel assembly.

15. While mast section-3 is still extended from section-2
remove the bolts attaching the two (2) cable assem­bly anchor eyelets to the TOP of mast section-3.
Remove cables.

NOTE: When sliding mast sections apart, be careful not to

scratch or score the anodized finish in the slide pad
channels.

16. Carefully slide mast section-3 out BOTTOM of sec­tion-2. Remove slide pads, shims and chain anchor
plate, if necessary.

NOTE: Removal of mast section-2 (cylinder attach section)

is basically the same for all VP model lifts except
where noted.

17. Slide mast section-2 out TOP of mast section-1 far
enough to allow access to the cable/chain assembly
anchor block/sheave wheel assembly.

18. Remove countersunk-flathead screws securing
cable/chain anchor block/sheave wheel assembly
attach bars on both side rails at TOP of mast sec­tion-2.

19. Slide the cable/chain anchor block/sheave wheel
assembly and hydraulic cylinder out the TOP of
mast section-2 far enough to allow removal of the
sheave wheel attach bars, sheave wheels and
sheave pin from cable/chain assembly anchor
block.

20. Remove the setscrew holding the hydraulic cylinder
rod into the chain assembly #444 anchor block. Lay
chain assembly #444 to side.

21. Remove the hydraulic cylinder through BOTTOM of
mast section-2, be careful not to nick or score cylin­der rod surface while removing.

NOTE: When sliding mast sections apart, be careful not to

scratch or score the anodized finish in the slide pad
channels.

22. Carefully slide mast section-2 out BOTTOM of sec­tion-1. Remove slide pads and shims, if necessary.

23. Slide the TOP of remaining mast section-1 out over
edge of work surface and remove the bolts attaching
the cable/chain anchor blocks to mast section-1.
Remove cable/chain assemblies from mast and lay
aside.

24. Remove slide pads and shims from mast section-1.

Mast disassembly should now be complete.

NOTE: Step 15 applies only to 20VP lift models which have

five (5) mast sections. If servicing a 15VP mast, go
to step 16.

3120728 – JLG Lift – 2-27

SECTION 2 - SERVICE PROCEDURES

Figure 2-19. 10VP Mast Assembly.

2-28 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

Figure 2-20. 15VP Mast Assembly.

3120728 – JLG Lift – 2-29

SECTION 2 - SERVICE PROCEDURES

Figure 2-21. 20VP Mast Assembly.

2-30 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

Mast Assembly

(See Figure 2-18., 2-19., 2-20. & 2-21.)

1. Place mast section-1, rail (open) side up on a clean,
flat surface (preferably a table or work bench capa-

ble of supporting the weight of the entire mast
assembly). Slide mast out over end of work surface

far enough to allow access to the chain anchor
attach holes at top of mast.

2. Locate the two (2) single cable/chain assemblies.
Lay out each cable/chain assembly with anchor
block end towards mast, and threaded end away
from mast, (be certain floor surface is clean and free

of any metal chips or debris which may stick to lubri­cated chains).

3. Insert the block anchor end into the top of mast sec­tion-1 and secure using two (2) 3/8"-16UNC x 2-1/2"
(chain) 1-1/4" (cable) long hex head bolts, flatwash­ers and nuts for each attach block. Place a flat­washer under bolt head and nut.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

4. Locate mast section-2, carefully slide mast section-2
closed rail into section-1 open rail. Slide sections
together until ends are even.

sure there are no air gaps (on flat side of slide
pad) between shims, shim and mast or shim and
slide pad when tightened.

c. All mast sections are to be shimmed to provide a

measurable gap between the slide pad (beveled
side) and mast channel of 0.012" to 0.025" per
side.

d. When mast slide pads are shimmed properly,

the mast sections should be able to slide in
channel by hand.

8. Insert slide pads into the slide pad channels (top of
mast) between section-1 and -2, (one on each side
of the mast), with beveled surface facing in towards

section-2.

9. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes in

mast section-1 outside rail (top of mast) and into the
slide pad inserts. Thread in enough to hold pad in
place.

10. Shim per instructions in step 7.

NOTE: If hydraulic cylinder needs to be extended, the pro-

tective caps on the extend and return ports will need
to be removed. Be careful not to nick or scour rod
surface when extending, also catch any oil draining
out of cylinder to avoid spillage onto work area.

NOTE: Do not attach mast slide pads and shims to mast

sections before assembling sections. If assembled in
this manner, due to the tight fit of the slide pads in
the slide pad channels, the anodized finish could be

removed from the receiving mast’s slide pad chan-
nels.

5. Insert slide pads into the slide pad channels at bot­tom end of mast between section-1 and -2, (one on
each side of the mast), with beveled surface facing
out towards section-1.

6. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes in

mast section-2 inside rail, into the slide pad inserts.
Thread in enough to hold pad in place.

7. Shim slide pads using the following steps:

NOTE: Always use the an even amount of shim material

behind slide pads on both sides of the mast rails.
This will keep mast sections centered in rail chan­nels and prevent any distortion of the mast section.

a. Use two shim pieces per slide pad, a thick one

and a thin one.

b. Start with a total thickness of approximately a

.025" thick shim and a .055" thick shim.Slide
shims into place between slide pad and mast
rail. Tighten the slide pad mounting bolts, be

11. Locate the hydraulic lift cylinder, slide the lift cylinder
into the closed rail side of mast section-2 with rod
end to top and port end to bottom of mast. Cylinder
should extend out of mast on both ends. Return
tube should be on right side when facing bottom of
mast assembly.

NOTE: Top of cylinder assembly steps 12 and 13 applies to

20VP only. For 10VP & 15VP continue to step 14.

12. Locate chain assembly #444 (single anchor block
with two narrow chains). Lay out chain assembly
with anchor block end towards mast, (be certain
floor surface is clean and free of any metal chip or
debris which may stick to lubricated chains).

13. Insert hydraulic cylinder rod end into chain assem­bly #444, anchor block. Secure cylinder rod to
anchor block with a 1/4"-28UNF x .50" long - Type C
setscrew. Coat threads with blue Loctite # 242
before assembly.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad rails.

a. Locate mast section-3, carefully slide section-3

closed rail into section-2 open rail. Slide sec­tions together until ends are even. Locate one
(1) of the chain/cable anchor plates (one with

threaded holes horizontally aligned to outside of

3120728 – JLG Lift – 2-31

SECTION 2 - SERVICE PROCEDURES

bracket). Attach using outer set of holes in bot­tom of mast section-3 with two (2) 1/4"-20UNC x
3/4" long bolts, place a flatwasher under head of
each bolt.

14. Slide mast section-3, approximately two feet out of
the top of mast section-2.

15. Insert threaded ends of cable/chain-assembly #466
(attached to top of mast section-1), through holes in
anchor plate attached to bottom of mast section-3.
Loosely thread two (2) 3/8"-16UNC nuts onto stud
threads on each chain. Cables/chains will be
adjusted later in assembly.

16. Slide mast section-2 out of mast section-1 approxi­mately one foot.

10VP Top of Cylinder Assembly

19. Assemble cable sheave wheels to cylinder rod end

and attach to mast section-2 using following steps;

a. Attach cable mounting tube to top of hydraulic

cylinder using one (1) 1/4"-28NF x 5/8" cap­screw.

b. Insert sheave pin through cylinder cable mount-

ing tube on cylinder rod end.

c. Place a spacer tube on each side of mounting

tube.

d. Next slide sheave wheels on onto sheave pin

against spacer, on each side of mounting tube.

e. On outside of each sheave wheel, place another

spacer tube.

f. On outside of spacer tubes place a sheave pin

attach bar, (rectangular plate with threaded holes
on each side of pin bore hole).

g. Slide the assembly with sheave pin, wheels and

pin attach bars into top of mast section-2.

h. Attach to top of mast section-2 using two (2) 3/

8"-16UNC x 1/2" long socket head-countersunk­flathead cap screws each side. Coat threads
with Loctite #171 and tighten.

15VP Top of Cylinder Assembly

19. Assemble cable sheave wheels to cylinder rod end

and attach to mast section-2 using following steps;

a. Attach cable mounting tube to top of hydraulic

cylinder using one (1) 1/4"-28NF x 5/8" cap­screw.

b. Insert sheave pin through cylinder cable mount-

ing tube on cylinder rod end.

c. Place a spacer tube on each side of mounting

tube.

d. Next slide sheave wheels on onto sheave pin

against spacer, on each side of mounting tube.

e. On outside of each sheave wheel, place another

spacer tube.

f. On outside of spacer tubes place a sheave pin

attach bar, (rectangular plate with threaded holes
on each side of pin bore hole).

g. Before sliding this assembly into the top of mast

section two, locate two (2) mast extension cable
assemblies and lay their anchor ends into the
slots of the cable mounting tube.

h. Slide the assembly with sheave pin, wheels and

pin attach bars into top of mast section-2.

i. Attach to top of mast section-2 using two (2) 3/

8"-16UNC x 1/2" long socket head-countersunk­flathead cap screws each side. Coat threads
with Loctite #171 and tighten.

20VP Top of Cylinder Assembly

19. Assemble chain sheaves on chain assembly #444

anchor block (attached to cylinder rod end) and
attach to mast section-2 using following steps;

a. Insert sheave pin through anchor block on cylin-

der rod end.

b. Place sheave wheels (for wide chain) on sheave

pin, one each side of anchor block.

c. On outside of each sheave wheel, place a

sheave pin attach bar, (rectangular plate with
threaded holes on each side of pin bore hole).

d. Slide the whole anchor block assembly with

sheave pin, wheels and pin attach bars into top
of mast section-2. (Position anchor block with
narrow chains facing mast section-3).

e. Attach to top of mast section-2 using two (2) 3/

8"-16UNC x 1/2" long socket head-countersunk­flathead cap screws each side. Coat threads
with Loctite #171 and tighten.

20. Slide mast section-2 back into section-1 until end
are even.

NOTE: Step 23 and 24 applies to 20VP mast assembly only.

10VP and 15VP mast assembly continue at step 25.

21. Locate two mast extension cable assemblies. Attach
the eyelet anchor end of each cable to the outside
holes near top of mast section-3 using 3/8"-16UNC x
1-1/4" long hex head bolts, nuts and flatwashers.
Place a flatwasher under bolt head and nut.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

22. Carefully slide mast section-3 into section-2 until
ends are even. Check to make sure chain assembly
#466 (wide chains) are seating properly in chain
#444 anchor block chain sheave wheels attached to
mast section-2.

NOTE: Do not attach mast slide pads and shims to mast

sections before assembling sections. If assembled in

2-32 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

this manner, due to the tight fit of the slide pads in
the slide pad channels, the anodized finish could be
removed from the receiving mast’s slide pad chan-
nels.

23. Insert slide pads into the top end mast rails between
section-2 and -3, (one on each side of the mast),
with beveled surface facing inward towards section-

3.

24. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes in

outside rail, on top of mast section-2 and into the
slide pad inserts. Thread in enough to hold pad in
place.

25. Shim per instructions in step 7.

26. Insert slide pads into the bottom end mast rails

between section-2 and -3, (one on each side of the
mast), with beveled surface facing out towards sec-

tion-2.

27. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes on

inside rail, on bottom end of mast section-3 and into
the slide pad inserts. Thread in enough to hold pad
in place.

28. Shim per instructions in step 7.

NOTE: Assembly of 10VP mast should now be complete. To

continue with 15VP assembly go to step 48. 20VP
assembly continues following.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

29. Locate mast section-4, carefully slide section-4
closed rail into section-3 open rail. Slide sections
together until ends are even.

30. Locate one (1) of the chain/cable anchor plates (one
with two threaded holes vertically aligned in center of
bracket). Attach through inner (vertical) set of holes

at bottom of mast section-4 using two (2) 1/4"­20UNC x 3/4" long bolts, place a flatwashers under
head of each bolt.

31. Slide mast section-4 out the top of mast section-3 so
the chain/cable anchor plate on bottom of mast sec­tion-4 is easily accessible at top end of mast section-

3. Rest the top end of mast section-4 on a support
while performing next step.

32. Insert threaded ends of cable/chain assembly

(attached to anchor block on top mast section-2)

through the chain/cable anchor plate located on bot­tom of extended mast section-4. Loosely thread two
(2) 3/8"-16UNC nuts onto stud threads on each
chain. Chains will be adjusted later in assembly.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

33. Slide mast section-4 back into mast section-3 except
for about a foot or more. Allow enough slack in
cables/chains to mount sheave wheels to top of
mast section-3.

34. Extend mast section-3 out far enough from section-2
mast to gain access to top of section-3.

35. Assemble cable/chain sheaves to top of mast sec­tion-3 as follows;

a. Locate the two cable/chain sheave wheels and

slide onto sheave pin.

b. Slide two (2) short spacer tubes onto sheave

pin, one each end of sheave pin to outside of
sheave wheels.

c. Place two (2) sheave pin attach bars, one each

end of sheave pin to outside of space tubes.

d. Holding complete sheave wheel assembly, slide

assembly into top of mast section-3 and align
threaded holes in sheave pin attach bars with
holes in mast rails.

e. Attach to top of mast section-3 using two (2) 3/

8"-16UNC x 1/2" long socket head-countersunk­flathead cap screws, each side. Coat threads
with Loctite #171 and tighten.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

36. Slide mast section-3 back into section-2 until ends
are even. (Mast section-2 may need to be restrained
to keep its slide pads from pushing out the bottom
of mast section-1).

37. While mast section-4 is still extended from section-3;
locate two cable assemblies. Attach the eyelet
anchor end of each cable to the inside set of holes
near top of mast section-4 using 3/8"-16UNC x 1-1/4"
long hex head bolts, nuts and flatwashers. Place a
flatwasher under bolt head and nut.

38. While mast section-4 is still extended from section-3,
assemble cable sheaves to top of mast section-4 as
follows;

a. Locate the wide tube spacer and slide onto

sheave pin.

b. Slide two (2) cable sheave wheels onto sheave

pin, one each end of sheave pin to outside of
tube spacer.

c. Place two (2) large flat washers, one each end of

sheave pin to outside of cable sheave wheels.

d. Place two (2) sheave pin attach bars, one each

end of sheave pin to outside of large flatwash­ers.

3120728 – JLG Lift – 2-33

SECTION 2 - SERVICE PROCEDURES

e. Holding complete cable sheave wheel assem-

bly, slide assembly into top of mast section-4
and align threaded holes in sheave pin attach
bars with holes in mast rails.

f. Attach to top of mast section-4 using two (2) 3/

8"-16UNC x 1/2" long socket head-countersunk­flathead cap screws, each side. Coat threads
with Loctite #171 and tighten.

NOTE: When sliding mast sections together, be careful not

to scratch or score the anodized finish in the slide
pad channels.

39. Carefully slide mast section-4 back into section-3
until ends are even. Check to make sure cable/chain
assemblies are seating properly in cable/chain
sheave wheels attached to top of mast section-3.

NOTE: Do not attach mast slide pads and shims to mast

sections before assembling sections. If assembled in
this manner, due to the tight fit of the slide pads in
the slide pad rails, the anodized finish could be
removed from the receiving mast’s slide pad chan-
nels.

40. Insert slide pads into the top end mast rails between
section-3 and -4, (one on each side of the mast),
with beveled surface facing inward towards section-

4.

41. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes in

outside rail, on top of mast section-3 and into the
slide pad inserts. Thread in enough to hold pad in
place.

42. Shim per instructions in step 7.

43. Insert slide pads into the bottom end mast rails

between section-3 and -4, (one on each side of the
mast), with beveled surface facing out towards sec-

tion-3.

44. Thread slide pad attaching bolts, (two (2) 1/4"-
20UNC x 3/8" long hex head bolts, place a flat
washer under head of each bolt), through holes on

inside rail, on bottom end of mast section-4 and into
the slide pad inserts. Thread in enough to hold pad
in place.

45. Shim per instructions in step 7.

NOTE: The platform mounting section (section—4 on 15VP

and section-5 20VP machines) slide pads, are
assembled differently than the slide pads for the
other mast sections. Mast section-4/-5 slide pads
may need to be assembled/disassembled several
times in order to determine the correct shim stock
required for proper fit.

46. Locate the remaining mast section-4/-5 (platform
mounting- mast section). Lay mast section on flat

stable surface.

47. Attach the remaining chain/cable anchor plate (one
with threaded holes vertically aligned in center of
bracket). Attach through inner (vertical) set of holes

in bottom of mast section-4/-5 with two (2) 1/4"­20UNC x 3/4" long bolts, place a flatwasher under
head of each bolt.

48. Complete the following steps to determine shim
stock thickness required for section-4/-5;

NOTE: Always use the an even amount of shim material

behind slide pads on both sides of the mast rails.
This will keep mast sections centered in rail chan­nels and prevent any distortion of the section.

a. Use two shim pieces per slide pad, a thick one

and a thin one.

b. Start with a total thickness of approximately

.035" and .075" thick shim stock.

NOTE: To protect the anodized finish when sliding the

assembled mast section-4/-5 into section-3/-4, grind
top and bottom edges of slide pads to approximately
a 1/4" radius.

c. Attach shim stock and slide pads to both sides

of mast section-4/-5 using five (5) 1/4"-20UNC x
1-1/4" long, hex head cap screws per side, with
flatwasher under each bolt head. (Assemble

shim stock and slide pad to mast section rail with
shim stock against rail and slide pad with bev­eled side out).

d. Carefully thread the slide pad mounting bolts

with flatwashers through slide pads and shim
stock into threads in mast section-4/-5. Be cer­tain there are no air gaps between shims, shim
and mast or shim and slide pad when tightened.

NOTE: When sliding mast section-4/-5 into section-3/-4 note

amount of force required to push sections together.
Fit should be very snug but still be able to be pushed
together by hand. If too tight, remove section-4/-5,
disassemble slide pad from section-4/-5 and reduce
thickness of shim stock. Open rails of section-3/-4
may be sprayed with silicone spray to help section-4/

-5 slide easier.

e. Begin sliding top of mast section-4/-5 with

closed rail down engaging the slide pads into
slide pad channels at bottom of mast section-3/­4’s open rail. Continue to push section-4/-5 into
section-3/-4 until BOTTOM ends of mast sec­tions are even.

f. Check mast section for side play. If play exists

use thicker shims dividing thickness equally
between both sides of mast.

2-34 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

g. When mast slide pads are shimmed properly,

there should be no side to side movement of
slide pad in rail channel. Mast sections should
be very snug in channels but still be able to slide
in channel by hand.

49. Slide mast section-4/-5 to top of section-3/-4.

50. Insert threaded ends of cable assembly (attached to

top of mast section—2/3) through the chain/cable
anchor plate located on bottom of extended mast
section-4/-5. Loosely thread two (2) 3/8"-16UNC
nuts onto stud threads on each chain. Chains will be
adjusted later in assembly.

51. Slide mast section-4/-5 back into mast section-3/-4
until bottom ends of masts are even. Check to make
sure cable set attached to top of section-2/-3 is seat­ing properly in cable sheave wheels attached to top
of mast section-3/-4. (Mast sections-2, -3 and -4 may

need to be restrained to keep their slide pads from
pushing out the bottom of mast sections-1, -2 and -

3).

52. At bottom of mast assembly, thread all chain/ cable
adjusting nuts on threaded ends until they are snug
against the anchor plates and all slack is removed
from chains and cables. Check that chains and
cables are seated in their sheave wheels at top of
mast assembly. Also, ends of mast sections should
be even with each other.

Mast assembly should now be complete.

2.10 MAST TO BASE FRAME INSTALLATION

IF BATTERIES ARE STILL MOUNTED, REMOVE BATTERIES FROM
THEIR TRAYS BEFORE LAYING THE BASE FRAME IN A HORIZON­TAL POSITION.

1. Using an overhead crane or suitable lifting device
capable of supporting the weight of the base frame,
attach a sling strap or chain to the front crossmem­ber of the base frame. Carefully tilt the base frame
back until the front is pointing up and the back is
resting on the counterweight/battery trays. Be sure
base is very stable and at a 90° angle to work sur­face before proceeding.

2. Using a sling and suitable lifting equipment (i.e.
overhead crane) lift the mast assembly (balanced in
middle) into position in front of the base frame.

3. Extend hydraulic cylinder out from bottom of mast
assembly approximately one (1) foot. (Caps on

extend and return ports will need to be removed to
extend cylinder. Catch any hydraulic fluid expelled
from return port in a container to prevent spillage
onto work area).

4. Carefully position the mast into base frame assem­bly, (base frame and mast assembly must be held at
90° angle to each other).

5. Slide port end of hydraulic cylinder through hole in
base frame cylinder mounting channel. (Return port

(tube side) of cylinder must be on right side facing
bottom of base and mast).

6. Align threaded hole in side of hydraulic cylinder
head with hole in tab on bottom side of cylinder
mounting channel. Secure hydraulic cylinder to cyl­inder mounting channel tab using a 5/16"-18UNC x
5/8" long hex head bolt and flat washer.

7. Carefully push mast assembly and base assembly
together until the four (4) holes on bottom rear of
mast align with holes in the base frame mast support
crossmember.

8. Attach mast to base using four (4) 3/8"-16UNC x 1"
long hex head bolts, locknuts and flatwashers,

(place a flatwasher under bolt head and nut and
mount with nuts on inside of frame).

9. Locate the two (2) mast support braces, attach to
sides of base frame using a 3/8"-16UNC x 1" long
hex head bolt, nut and flatwashers each brace,

(place a flatwasher under bolt head and nut and
mount with nuts on inside of frame. Use access hole
in bottom of frame to attach nut inside frame).

10. Before setting machine upright on base, install a
short 90° elbow fitting, flow control valve and
another short 90° elbow fitting on the end of the flow

3120728 – JLG Lift – 2-35

SECTION 2 - SERVICE PROCEDURES

control valve in the extend (left) port on bottom of
hydraulic cylinder. Install a long 90° elbow fitting on
return (right) port. Use sealant tape on fitting
threads. Cap ports until hydraulic lines are installed.

11. Carefully set machine in an upright position on its
base frame wheels.

12. Locate the mast support bracket. Attach mast sup­port bracket to mounting holes halfway up back of
mast using four (4) 3/8"-16UNC x 2-3/4" long hex
head bolts, locknuts and flatwashers. (Place a flat-

washer under bolt head and nut and mount with nuts
on inside of frame).

13. Using a 4 ft. level, ensure the mast is set to vertical

(plumb) on the base frame.

14. When mast is vertical (plumb), attach support
braces, (bolted to base), to the mast support
bracket, (bolted to mast), using 3/8"-16UNC x 2-3/4"
long hex head bolts, nuts and flatwashers. (Place a

flatwasher under bolt head and nut and mount with
nuts on inside of bracket).

15. After securing mast to base frame, using 4 ft. level
again check that mast is vertical (plumb) on base
frame.

16. Continue installing remaining components to mast
assembly, (i.e. hydraulic pump/motor/reservoir, bat-
tery charger, etc.) until machine is complete.

2.11 MAST CHAINS/CABLES AND
SEQUENCING CABLES ADJUSTMENT

Mast Chain/Cable Adjustment

The intention of this procedure is to assure equal load dis­tribution between the individual chains/cables of a mast
section chain/cable set.

Adjust using the following procedure;

1. With mast retracted, step into the platform and
bounce your weight up and down a few times to be
certain platform is at the bottom of travel. Be certain
all chain/cable sets are seated in their sheaves prop­erly at the top of each mast section.

2. Then with no load in the platform check the side pro­file of the top of the mast for the amount of adjust­ment necessary to make the mast sections even for
mast sections-3 and up. (See Figure 2-22.)

NOTE: Mast section-1 is fixed to the base and mast section-

2 is attached to the lift cylinder, these sections
require no adjustment.

3. Adjust one mast section at a time starting from the
back (section-3, section-4, etc.) of the mast and
work forward. (i.e.. if three is OK, then jump to four,
etc.)

4. Elevate the platform until the chain/cable anchor
adjust nuts are accessible at the front and bottom of
each mast section.

NEVER WORK UNDER AN ELEVATED PLATFORM UNTIL PLAT­FORM HAS BEEN SAFELY RESTRAINED FROM ANY MOVEMENT
BY BLOCKING OR OVERHEAD SLING.

5. Start with the mast section which needs adjustment
and loosen the bottom (jam) nut on each chain/
cable.

6. Tighten (to raise mast section), or loosen (to lower
mast section) the adjusting nut against the anchor

plate on each chain/cable. Adjust the nut the
amount required to raise or lower the top of the mast
section so it is even with the previous mast section
when the mast is retracted. Be certain each chain/
cable pair is adjusted to equal tension. (The

threaded end of the chain/cable will need to be
restrained while tightening the adjust nut to keep the
chain/cable from twisting.)

7. Retract the mast all the way and check if the top of
the mast sections appear as shown in Figure 2-22.

8. Repeat steps (1) through (7) for remaining mast sec­tions. ENSURE THAT ALL CHAIN/CABLE PAIRS
HAVE EQUAL TENSION.

2-36 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

p

MAST SIDE PROFILE

ADJUST UNTIL TOPS OF MAST

SECTIONS ARE EVEN

MAST CHAIN/CABLE ADJUSTERS

MAST COVER

SHOWN REMOVED

SEQUENCE CABLE

ADJUST NUT

SECTION-1

FIXED

TO BASE

SECTION-2

EXTENDED BY

CYLINDER

SECTION-3

EXTENDED BY

CHAIN

SECTION-4
EXTENDED BY
CHAIN/CABLE

SECTION-5

(PLATFORM

HEADER SECTION)

EXTENDED BY

CHAIN/CABLE

Note: When

a

threads under the jam nut.

Figure 2-22. Mast Chain/Cable/Sequence Cable Adjustment Components.

9. Once mast section adjustment is completed, apply

loctite #242 to the threads under the (jam) nuts that
were loosened. Then re-tighten the loosened (jam)
nuts until tight against the top (adjust) nut. Chain/
cable should have slight tension but should not be
taut.

Sequencing Cable Adjustment

1. Retract mast completely, and check each sequenc-

ing cable on outside of masts for excessive slack.
Adjust only to remove slack from cable.

chain adjustment

is complete, before

tightening the jam nut

against the adjust nut,

ply Loctite #242 to the

.

CHAIN/CABLE

ANCHOR PLATE

ADJUST NUT

JAM NUT

THREADED

CHAIN/CABLE

END

2. Tighten nylock-nut just enough to remove excessive
slack from sequencing cable. The springs should
not be compressed more than 25% after adjusting.

3. Run mast through several cycles to verify cable/
chain adjustments and ensure no interference exists
between chain anchor brackets and mast.

3120728 – JLG Lift – 2-37

SECTION 2 - SERVICE PROCEDURES

2.12 SEQUENCE CABLE REPLACEMENT KIT

A sequence cable replacement kit is available from the
JLG Parts Department to service broken or worn
sequence cables. This kit consists of a replacement
sequence cable with the threaded (top) end attached
same as the top end of the factory cable. Also included is
a clamp (drum/socket type) to secure the bottom end of
the cable. Use the following procedure to install the
replacement cable and clamp kit.

Remove Old Cable

1. Remove the locking nut from the threaded end of

the cable at the top of the mast and then remove the
spring cap, spring, and spacer washers if installed.

2. Slide the threaded top end out of the upper anchor
bracket, then at the bottom end pull the cable out
though the sheave pulley/anchor bracket until it is
completely clear of the machine.

Replacement Cable Installation

1. Be certain the mast is completely retacted and at the

bottom of travel. Check the mast "Side Profile" at the
top of the mast as shown in Figure 2-22., adjust
mast sections to proper height if necessary.

2. To determine where the clamp will be installed at the
bottom of the replacement cable, temporarily
assemble the new replacement cable to the top
cable anchor bracket on the mast using the wash­ers, spring, spring cap and lock nut previously dis­assembled. Thread the lock nut on until
approximately 1/8 in. (3mm) of threads are exposed.

3. At the bottom of the mast, thread the loose end of
the replacement cable through the proper sheave
pulley and through the hole in the sheave pully/
anchor bracket on the mast section ahead of the
sheave pulley.

4. Grasp the cable and pull on the cable until the
spring at the top of the cable is slightly compressed.
Use a black marker to mark the cable on the top
side of the sheave pully/anchor bracket. This will
determine where the clamp (drum/socket) sleeve will
be positioned on the cable.

Clamp Installation (Drum/Socket Type)

THE MANUFACTURER OF THE DRUM/SOCKET CLAMP RECOM­MENDS THE USE OF THEIR CABLE CLAMP ASSEMBLY KIT (JLG
P/N - 7023275) TO ASSEMBLE THE CLAMP TO THE WIRE ROPE.
THE KIT CONSISTS OF VISE JAWS TO HOLD THE WIRE ROPE IN
A VISE PROPERLY WITHOUT DAMAGING ANY ROPE STRANDS
AND A PLUG DRIVER TO DRIVE THE PLUG INTO THE CENTER OF
THE WIRE ROPE AND IS ALSO USED TO FORM THE STRANDS OF
THE ROPE DURING ASSEMBLY.

NOTE: The tools in the clamp assembly kit may be frabri-

cated if necessary. The vise clamp consists of vise
jaws with a hole drilled 1/32 in. smaller than the
diameter of the wire rope you are working with (i.e.
1/8 in. rope - 3/32 in. hole.)
The plug driver is a metal tube with a hole in the bot­tom to allow the strands of the wire rope to be
shaped after the plug has been tapped into the cen­ter of the wire rope.

1. Using the recommended vise jaws, clamp the wire
rope into a vise with the bottom edge of the black
mark made on the wire rope resting just above the
vise jaws.

2. Twist the sleeve from the clamp kit onto the rope
until it is flat against the vise jaws at the mark made
made on the wire rope.

DO NOT CUT THE CABLE AT THE MARKED POINT ON THE
CABLE THIS IS ONLY USED AS A REFERENCE FOR POSITIONING
THE CABLE SLEEVE WHICH WILL REST AGAINST THE ANCHOR
BRACKET ONCE INSTALLED.

2-38 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

3. Use a suitable tool and cut the cable as shown in the
illustration following. For 1/8 in. cable the recom­mended length is 5/8 in. past the end of the sleeve.

4. Unlay the cable strands by gently forcing a screw­driver between the outer strands to unlay the cable.
When done properly the outer strands will form a
symmetrical basket. Do not straighten out the spiral
lay of the strands, unlay any wires that make up the
strand, or allow the strands to cross each other
inside the sleeve.

6. Reclamp the assembly in the vise on the flats of the
sleeve. Using the plug driver, a metal tube or pliers,
bend the outer strands toward the center strands
enough that the socket can be slipped over all the
strands.

NOTE: When assembling stainless steel parts all threads

must be coated with a dry lubricant or an anti-sieze
lubricant to prevent seizing.

7. Coat the threads of the socket and sleeve with lubri­cant and install the socket by twisting it over the
strands of the cable and engage the threads of the
sleeve with the socket. Tighten until four threads or
fewer are visible. If more than four threads are visi­ble, proof load the cable and retighten the socket fit­ting. (There is no specific requirement for torque.)

5. Install the plug supplied with the kit by placing the
plug in the center of the strands starting with the
small tapered end of the plug. Use a metal tube
(plug driver) and hammer to drive the plug into the
sleeve while assuring that the strands are spaced
somewhat equally around the plug. Drive the plug
until it is firmly seated and no more than 1/3 of the
plug is visible from above the sleeve.

8. Inspect for proper assembly prior to loading the
cable. Strands visible through the inspection hole
are your assurance of a proper assembly.

NOTE: The end of the rope may not be visible in the inspec-

tion hole after loading.

9. Install cable on machine and adjust per instructions
shown previously in Section 2.11, MAST CHAINS/
CABLES AND SEQUENCING CABLES ADJUST­MENT.

3120728 – JLG Lift – 2-39

SECTION 2 - SERVICE PROCEDURES

2.13 PREVENTIVE MAINTENANCE AND
INSPECTION SCHEDULE

(See Table 2-2.)

The preventive maintenance and inspection checks are
listed and defined in the following table (See Table 2-2.,
this chapter). This table is divided into two basic parts, the
“AREA” to be inspected and the “INTERVAL” at which the
inspection is to take place. Under the “AREA” portion of
the table, the various systems along with the components
that make up that system are listed. The “INTERVAL” por-
tion of the table is divided into five columns representing
the various inspection time periods. The numbers listed
within the interval column represent the applicable inspec­tion code for which that component is to be checked.

The checks and services listed in this schedule are not
intended to replace any local or regional regulations that
may pertain to this type of equipment nor should the lists
be considered as all inclusive. Variances in interval times
may occur due to climate and/or conditions and depend­ing on the location and use of the machine.

JLG Industries requires that a complete annual inspection
be performed in accordance with the “Annual Machine
Inspection Report” form. Forms are supplied with each
new machine and are also available from JLG Customer
Service. Form must be completed and returned to JLG
Industries.

JLG INDUSTRIES REQUIRES THAT A COMPLETE ANNUAL
INSPECTION BE PERFORMED IN ACCORDANCE WITH THE
“ANNUAL MACHINE INSPECTION REPORT” FORM.

2-40 – JLG Lift – 3120728

SECTION 2 - SERVICE PROCEDURES

Table 2-3. Preventive Maintenance & Inspection Schedule.

AREA ON MACHINE INTERVAL

PLATFORM

Platform Controll er (all functions) 1,11
Placards and De cals 1,2
Control Tags 1,2
Electrical Cables 1,8
Handrail and Bar Gate 1,4

MAST

Mast Chains/Cables /and all component parts 1,4,7,9 12
Mast Section s 1,4,7
Mast Sequencing Cables 1,4,7,9
Speed/PHP Limit Switc hes 1,7,9

BASE FRAME

Batteries 1,3 5
Battery Charge 1
Power Cable s To Platf orm 1,8
Electric Motor/Hyd raulic Pump Unit 1 5
Hydraulic Hoses and Fittings 1 5
Hydraulic Oil Reservoir * 3 5 4
Hydraulic Oil Re servoir Breather 6,14
Manual Descent Valve 1,7
Lift Cylinder 1 5,6,13 4
Placards and De cals 1,2
Wheels and Caste rs 1 8,9 12
Wheel Bearings 8 12
Electric Drive Wheel Moto rs 1 ,7
Electric Drive Wheel Gear Box **
Torque Limitin g Clutch 1,6,9
Power Switch (Ground Con trol Box) 1,11
Control Tags 1,2
Hoses and Cables 1,8
Bubble Level Indicator 1,2

* Inspection and Maintenance Code 10 to be performed every two years.
** Maintenance Code 10 to be performed only when serviced, requires 6 oz. (175 cc’s) to fill.

(10 HRS.)

DAILY

(50 HRS.)

WEEKLY

(200 HRS.)
MONTHLY

(500 HRS.)
3 MONTHS

(1000 HRS.)

6 MONTHS

(2000 HRS.)

1 YEAR

Inspection and Maintenance Codes:

1. Check for proper and secure installation.

2. Check for visible damage and legibility.

3. Check for proper fluid level.

4. Check for any structural damage; cracked or broken

welds; bent/warped surfaces; broken cable strands.

5. Check for leakage.

6. Check for presence of excessive dirt or foreign

material.

7. Check for proper operation and freedom of move­ment.

8. Check for excessive wear or damage.

9. Check for proper tightness and adjustment.

10. Drain, clean and refill.

11. Check for proper operation while pump/motor is

running.

12. Check for proper lubrication.

13. Check for evidence of scratches, nicks or rust and

for straightness of rod.

14. Check for condition of element; replace as neces­sary.

3120728 – JLG Lift – 2-41

SECTION 2 - SERVICE PROCEDURES

This page intentionally left blank.

2-42 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

SECTION 3. TROUBLESHOOTING

3.1 GENERAL

This section contains troubleshooting information to be used for locating and correcting most operating problems on a VP
Series Personnel Lift. If a problem should develop which is not presented in this section or which is not corrected by listed
corrective actions, technically qualified guidance should be obtained before proceeding with any maintenance.

3.2 TROUBLESHOOTING INFORMATION

Troubleshooting procedures applicable to the VP machine are listed and defined starting with Section 3.5, TROUBLE­SHOOTING SECTION - TABLE OF CONTENTS in this chapter of the manual.

Each malfunction within an individual group or system is followed by a listing of probable causes which will enable determi­nation of the applicable remedial action. The probable causes and the remedial action should, where possible, be checked
in the order listed in the tables.

It should be noted that there is no substitute for a thorough knowledge of the equipment and related systems.

It should be recognized that the majority of the problems arising in the machine will be centered in the hydraulic and electri­cal systems. For this reason, every effort has been made to ensure that all likely problems in these areas are given the fullest
possible treatment. In the remaining machine groups, only those problems which are symptomatic of greater problems
which have more than one probable cause and remedy are included. This means that problems for which the probable
cause and remedy may be immediately obvious are not listed in this section.

The first rule for troubleshooting any circuit that is hydraulically operated and electrically controlled is to determine if the cir­cuit is lacking hydraulic oil and electrical control power. This can be ascertained by overriding the bypass valve (mechani­cally or electrically) so that oil is available to the function valve, then overriding the function valve mechanically. If the function
performs satisfactorily, the problem exists with the control circuit.

3.3 HYDRAULIC CIRCUIT CHECKS

(See Figure 3-6.)

The first reference for improper function of a hydraulic system, where the cause is not immediately apparent, should be the
Hydraulic Diagram Circuit. The best place to begin the problem analysis is at the power source (pump). Once it is deter­mined that the pump is serviceable, then a systematic check of the circuit components, would follow.

NOTE: For aid in troubleshooting, refer to Figure 3-6. for HYDRAULIC DIAGRAM circuit.

3.4 ELECTRICAL CIRCUIT CHECKS

General

The drive system on the VP series machine requires a microprocessor controlled electrical circuit to operate smoothly and
accurately. All platform control functions are relayed to various machine components (i.e. platform up/down, drive functions,
etc.) through the (MC-1) microprocessor box (mounted under the battery charger support bracket).

To help diagnose any problems with the components associated with the microprocessor, the MC-1 is designed with an
internal fault messaging system which is displayed by LED flash sequences on the platform controller. When operating nor­mally the LED panel on the platform controller (center LED strip) indicates the battery voltage status using ten (10) green
LEDs. If a malfunction occurs to any of the drive components, the platform controller, or the MC-1 unit itself, these LEDs will
flash a fault code (Warning or Error type) to help locate the problem area. The possible causes of fault codes are outlined in
the following sub-sections of this chapter, see Table 3-1 and Table 3-2.

NOTE: For aid in troubleshooting electrical problem, refer to Figure 3-3. for an ELECTRICAL DIAGRAM of the various circuits.

Also a pictorial overview of the Section, see Figure 3-2. “Pictorial Overview of VP Electrical System”.

3120728 – JLG Lift – 3-1

SECTION 3 - TROUBLESHOOTING

Figure 3-1. LED Battery/Fault Code Indicator Strip

LED
INDICATOR
STRIP

on Platform Controller Box.

LED Indicator Strip

When the machine is powered up, all function inputs should be open. If any function is active on power up, all functions will
be made inoperative and a fault will be indicated at the platform controller box LED strip.

This strip has ten (10) green LEDs and is located on the platform controller box between the function touch pad buttons. See
Figure 3-1.

Fault Code Reference Tables

Their are two types of fault codes which can occur to indicate a problem with the machine, these are WARNING codes and
ERROR codes.

The fault codes can occur either at machine power up or during operation of the machine.

WARNING Codes

(See Table 3-1.)

The WARNING will be indicated for 4 seconds and will be repeated every minute if the problem is not corrected. An audible
three beeps indication is given at the beginning of each warning displayed. WHEN A WARNING CODE IS INDICATED THE
MACHINE WILL USUALLY FUNCTION, however some machine functions may be disabled. See Table 3-1. for explanation of
WARNING codes.

ERROR Codes

(See Table 3-2.)

An ERROR is indicated by an audible beep and continuously fast flashing LED bar. The number of fast (rapidly) flashing
LEDs indicate the particular error message. AN ERROR CONDITION WILL DISABLE THE MACHINE until the problem is cor­rected. The ERROR message is only reset by turning off the system, however if the problem has not been corrected the
ERROR will be indicated again at machine power-up. See Table 3-2. for explanation of ERROR codes.

NOTE: As shown in the following WARNING and ERROR code tables, a specific number of LEDs flashing can indicate more

than one WARNING or ERROR code. These tables suggest specific areas to check as the probable cause for the fault
code which has occured. The fault code number is shown in the first column of the table and the number of LEDs flash­ing on the platform controller LED strip is shown in the second column of the table.

3-2 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-1. MC-1 WARNING CODES

(Indicated by 3 beeps, then slow flashing LED’s)

WAR NING

CODE

010

LED’S

FLASHING

PROBABLE CAUSE REMEDY

Enter Code - Security Code has been activated and
must be entered before operation

Enter Code or deactivate using MC-1 configuration
software.

1 8 Charger Connected Unplug Charger

32

32

32

32

Brake Status Switch Open - Parking brake manually
released

Brake manual release lever obstructed (located at
drive motor brake)

Defective parking brake status switch (located at
drive motor brake)

Defective pin 11 at X105 (BRN wire) connection or
improper wiring

Reset Parking Brake

Clear obstruction and reset lever

Replace Switch

Properly attach wires or pin

3 2 Improper wiring at parking brake status switch Properly attach wires

32

45

56

Improper wiring from parking brake status switch to
ground

Configuration Lost - Drive Characteristic has
changed

Current Measurement faulty - Drive characteristic
may have changed

Prop erly at tach w ires

Repro gram using MC-1 software

Cycle on-off and reprogram if necessary

6 7 High Temperature in controller Reduce power

7 7 Motor Stalled Check drive wheels and motors

9 1 Battery Low ( < 18v) and power reduced Charge Batteries

12 9 Speed Control Potentiometer defective Replace Joystick

13 4

13 4

13 4

14 3

Drive Cutout Input Open - PHP bar must be d own to
drive whil e elevated

PHP bar is down, but drive is disabled - Defective wir­ing at D-connector

PHP bar is down, but drive is disabled - Defective
ground wiring

PHP bar is down, but drive is disabled - Defective
switch

Lower PHP

Properly attach wire (RED/BLU) or pin 12 of X105
connector

Prop erly at tach w ires

Repla ce switch

14 3 Tilt Switch open - Slope greater than 2 degrees Lower Platform and move to level ground

14 3

No Tilt Switch - open circuit at Pin 2 of X101 (WHT
wire)

Properly attach pin or wire connections

14 3 No Tilt Switch - open circuit to ground Check ground wire connections (BLK1 wire)

25 ---- Joystick E. Stop Counter Controller Log Only

26 ---- Configuration Access Counter Controller Log Only

3120728 – JLG Lift – 3-3

SECTION 3 - TROUBLESHOOTING

(Indicated by rapid LED flashing and periodic beep)

Table 3-2. MC-1 ERROR CODES

ERROR

CODE

LED’S

FLASHING

PROBABLE CAUSE REMEDY

0 8 System Overvoltage - Charger Unplug Charger

0 8 System Over voltage - Driving down long steep grade Operate ground controls to reduce voltage

1 7 Controller Over temperature Turn unit off and allow to cool

28

28

Drive Motor Plug - Open Circuit - check connectors
X103 & X104

Drive Motor Plug - Open Circuit - check motor con­nections at motor

P ro p er ly at ta ch w ir e s o r p in s A 1 & A 2

Properly attach wires or pins (WHT & BLK wires)

3 6 Brake Safety Relay Replace Controller

4 2 Brake Shor t Circuit Replace Brake

52

52

52

62

Brake Left Open Circuit - D-connectors to X103 &
X104 switched

Brake Left Open Circuit - Check pins 3 & 5 of X103
and brake wires

Brake Left Open Circui t - Check brake wires or plug at
drive motor

Brake Right Open Circuit - Check pins 2 & 5 of X104
and brake wires

Switch D-connectors - Left Motor to X103; Right
Motor to X104

Prop erly at tach w ires or pi ns

Prop erly at tach w ires or pi ns

Prop erly at tach w ires or pi ns

62

Brake Right Open Circuit - Check brake wires or plug
at drive motor

Prop erly at tach w ires or pi ns

7 2 Brake Open Circuit on one or both brakes See above

8 9 Switch Shor t Circuit (Joystick) Replace Joystick Box

9 6 Power Circuit Defect Replace Controller

10 1 Battery Low (< 16.5 v) Charge Battery

11 9

Check pins & wire connections at X102 & joystick
box connector

Prop erly at tach w ires or pi ns

11 9 Joystick defective Replace Joystick Box

12 8

Check pins & wire connections at X102 & joystick
box connector

Prop erly at tach w ires or pi ns

12 8 Joystick Box Replace Joystick Box

16 7

Current Limiting - Motor Shor t Circuit - Gearmotor
defective

Replace Gearmotor

21 6 36v supply Replace controller

24 5

Configuration Lost Reprogram using MC-1 sof tware, if error reoccours

then replace controller

25 6 RAM ROM Replace controller

3-4 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-2. MC-1 ERROR CODES

(Indicated by rapid LED flashing and periodic beep)

ERROR

CODE

LED’S

FLASHING

PROBABLE CAUSE REMEDY

If voltage @ pin 5 (RED2) of X101 is 20v w/24v @ Battery or if ground controls and operating lift up clears
error:

26 6

Defective main contactor Replace main contactor

Battery cables loose or corroded Clean & tighten battery cables

26 6

If 0v @ pin 5 of X101, check connection @ pin 7 &
14 of X102

Properly attach wires or pins

26 6 Connection @ pin 5 of X101 bad Properly attach wires or pins

26 6 Defective Power Relay Replace Relay

26 6 Defective Power Relay ground wire Properly attach wire

27 6

27 6

27 6

Safety Circuit - Joystick - check pin 6 @ X102 (Red
Wire)

Safety Circuit - Joystick - check pin 3 @ joystick
connector (Red Wire)

Defective Joystick - Normal voltage @ pin 6 of X102
(Red Wire): Joystick centered 5v, Joystick not cen-

Properly attach wire or pin

Properly attach wire or pin

Replace Joystick

tered 0v

27 6 Safety Circuit - Defective Controller Replace Controller

28 6 Current Measurement Replace Controller

29 6 Drive Circuit Lef t - Defective Controller Replace Controller

31 6 Drive Circuit Right - Defective Controller Replace Controller

32 1

Output driver defect - check for short in Hourmeter,
Horn, Alarm or Power Relay

Replace defective component

32 1 Output Driver Defective - Defective Controller Replace Con troller

35 8

35 8

Communication Error - Check Pins 5 & 13 of X102
(Orange & Blue Wires)

Communication Error - Check Pins 4 & 5 at Joystick
(Orange & Blue Wires)

Properly attach wires or pins

Properly attach wires or pins

35 8 Defective Joystick Replace Joystick

35 8 Defective Controller Replace Controller

36 6 Watch Dog Replace Controller

38 6 EEPROM Replace Controller

39 6 Software Error Replace Controller

3120728 – JLG Lift – 3-5

SECTION 3 - TROUBLESHOOTING

BEACON

TO (—)

BATTERY

TERMINAL

BATTERY
(LEFT SIDE)

HORN

(–

)

(+

ALARM

HOURMETER

BATTERY
(RIGHT SIDE)

(+

)

(–

)

TO PUMP
MOTOR
SOLENOID

)

F

R

O

C

M

O

X

N

1

N

0

E

1

C

T

O

R

PUMP START
CONTACTOR

MANUAL
OVERRIDE/
LIFT DOWN

VALVE

PUMP/MOTOR
ASSEMBLY

Figure 3-2. Overview of Standard Electrical System. (Sheet 1 of 2)

DUMP

VALVE

GROUND
CONTROL
BOX

CONTACTOR

EARLY

DESIGN

LATER

DESIGN

POT-HOLE

PROTECTION

LIMIT

SWITCHES

MAIN

RELAY

F
CO

5

10

R

X

O

M

CT

O

E

R

N

N

C

F

O

R

N

O

TA

M

R

E

C

L

T

A

O

Y

R

3-6 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

TO (+)

BATTERY

TERMINAL

TERMINAL

(

)

S

CONTROLLER BOX

LAPTOP COMPUTER

at X105 port on the MC-1 controller box

Requires P/N-2900868 Configuration Kit.)

X104

X101

X105

X103

TILT
SENSOR
SWITCH

(remove existing connector

and plug-in the laptop computer.

PLATFORM

CONTROL

BOX

TO (—)
BATTERY

USE WIRING

DIAGRAM

FIGURE 3-3.

THIS SECTION

OF THE

MANUAL WITH

THIS PICTORIAL

WIRING DIAGRAM

ELEVATION

LIMIT

SWITCH

F

R

O

M

X

1

0

C

O

N

1

N

E

C

T

O

R

TO

BATTERY

CHARGER

CUTOUT

SWITCH

5

0

1

R

X

O

M

T

O

C

E

R

F

N

N

O

C

GROUND

CONTROLS

SWITCH

(LIFT UP/LIFT DOWN)

GROUND

CONTROLS

RELAY

EXTERNAL

DRIVE/HORN

RELAY

CONTACTOR

RELAY

T

O

M

A

N

C

I

N

O

T

A

C

T

O

R

E

Y

A

L

PLATFORM

CONTROLLER

MC-1

DRIVE MOTOR

BRAKE

POWER LEAD

RELEASE

WIRING

BRAKE

RELEASE

WIRING

R

DRIVE MOTOR

POWER LEADS

MOTOR/BRAKE

ASSEMBLY

LEFT SIDE

BRAKE LIMIT

SWITCH

WIRING

MOTOR/BRAKE

ASSEMBLY

(RIGHT SIDE)

Figure 3-2. Overview of Standard Electrical System. (Sheet 2 of 2)

3120728 – JLG Lift – 3-7

SECTION 3 - TROUBLESHOOTING

8

TAN 4- 1

TAN 3- 1

TAN 55 -1

BLU/ORN 52-2

ORN/RED 49-5

ORN/RED 49-6

BLACK (10)

YEL/RED 2-5(10)

X101
B+
B+ CONTROL
MAIN POWER DISCONNECT
ELEVATION SWITCH
TILT CUTOUT
CHARGER INTERLOCK
B–

X102
B+
EMERGENCY STOP
CAN-LO
CAN-HI
CENTER DETECT
B–
EMERGENCY STOP

X103 – LEFT MOTOR
MOTOR 1
MOTOR 2
BRAKE 1
BRAKE2

MOTOR

RIGHT

BLACK

WHITE

PIN

A1

3
5
1
2
4

A2

PIN

15
14
13

5
6
1
7

PIN

A1
A2

5
3

X104 – RIGHT MOTOR
MOTOR 1
MOTOR 2
BRAKE 1
BRAKE 2

+

BRAKE

RIGHT

E-STOP SWITCH TO PIN 2
ON METAL BOX AND TO

PIN 1 ON PLASTIC BOX.

PIN 1 ON METAL JOYSTICK

PIN 2 ON PLASTIC JOYSTICK

JOYSTICK

BOX

PIN

A1
A2

5
2

ORANGE 55-6 (10)

ORANGE 55-4

ORANGE 55-5

ORANGE 55-3 (10)

PINS USED FOR
COMMUNICATION
TO SERIAL PORT
ON LAPTOP OR PC.

RX DO - RECEIVE DATA
TX DO - TRANSMIT DATA
GROUND
LIFT UP
LIFT DOWN
PUMP CONTACTOR
DRIVE CUTOUT

X105

9

345627

1

BRAKE STATUS
HORN
ALARMS
HOURMETER

RED/BLK

BLU/BLK

YEL

ORG

BLU

RED

BLK

BRN

24V

LOGIC POWER

EMERGENCY STOP

15 87135 6141

X102

A1

55
1
33
4
2

A2

X104

MC-1

CONTROLLER

0V

CAN-L

CAN-H

CENTER DETE CT

EMERGENCY STOP SWITCH

ORN/RED 49-1

14 12

ORN/RED 49-3

X105

11

6
4
5

3
15

PIN

7
8

13

4
6

5
12
11
15
14

3

BLU/ORN 52-1

BLU/ORN 52-3

+

LEFT

MOTOR

BLACK

WHITE

LEFT

BRAKE

ORANGE 55-7(10)

ORANGE 55-8

ORANGE 55-9

ORANGE 55-10(10)

A1

1
2
4

X103

A2

X105 X101 X104

X102 X103

A1

3

5

1

X101

2

4

A2

YEL/RED 2-2

YEL/RED 2-3

ORN/RED 49-7

END VIEW OF MC-1 BOX

4932960 A

SHOWING X CONNECTOR LOCATION

Figure 3-3. VP Electrical Diagram. (VP Series - Standard)

3-8 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

ORN/RED 49-2

12V

KEY SWITCH

YEL/RED 2-8

1

A

B

YEL/RED 2-1

YEL/RED 2-7

A

B

CONTACTOR

ORN/RED 49-1

BLU/ORN 52-1

ORN/RED 49-3

TAN 4 -1

TAN 3-1

TAN 55-1

BLU/ORN 52-3

BLACK

A

HORN

RELAY

YEL/RED 2-5(10)

YEL/RED 2-2

YEL/RED 2-3

ORN/RED 49-5

ORN/RED 49-6

ORN/RED 49-7
BLACK (10)

85
30

86

87

87A

YEL/RED 2-5

BLU/ORN 52-2

EXTERNAL

HORN

OPTION

BLU/ORN

52-4

HOURMETER

BLACK

A

ORN/RED 49-1

OPTION

86

LIMIT SWITCH

BLU/ORN 52-1

00000

BLACK

87

85

BLACK

A

LEFT PHP

ORN/RED 49-3

YEL/RED 2-4

87A

30

POWER

RELAY

ELEVATION / SPEED

CUTBACK SWITCH

TRAVEL, DESCENT,

MOTION ALARM

BLACK

RIGHT BRAKE
LIMIT SWITCH

N.O.H.C.

LIFT DOWN

TAN 4 -1

A

OPTION

ORN/RED 49-4

LIFT UP/DOWN

BLACK

BLACK

RIGHT PHP

LIMIT SWITCH

A

TAN 55-1

YEL/RED 2-2

MAIN

CONTACTOR

A

A

LEFT BRAK E

LIMIT SWITCH

N.O.H.C.

SWITCHGROUND CONTROL

YEL/RED 2-6

LIFT UP

5 AMP

RED (10)

FUSE

BLACK

BLACK

BLACK 55-2

RED 1-1

12V

BLACK (10)

A

A

YEL/RED 2-6

TAN 55- 1

KEY SWITCH

RED 1-1

GROUND CONTROL BOX

YEL/RED 2-4

YEL/RED 2-5

PUMP

MOTOR

PUMP

GROUND

CONTROL

RELAY

86

85

A

87

87A

30

A

FUSE

5 AMP

YEL/RED 2-6

E-STOP

YEL/RED 2-5

BLACK

23

X

GREEN

WHITE

TILT SENSOR

BLACK

BLACK

A

1.5°

CHARGER

1 = PLATFORM
2 = OFF
3 = GROUND

4932960 A

X

Figure 3-3. VP Electrical Diagram. (VP Series - Standard)

3120728 – JLG Lift – 3-9

SECTION 3 - TROUBLESHOOTING

TERMINAL

BEACON

GROUND

CONTROL

CONTACTOR

PROTECTION

BATTERY
(LEFT SIDE)

HORN

(–

)

(+

MOTION

ALARM

HOURMETER

BATTERY
(RIGHT SIDE)

(+

)

(–

)

TO PUMP
MOTOR
SOLENOID

80 AMP FUSE

)

MASTER ON/OFF

SWITCH

MAIN

RELAY

F

R

O

M

C

X

O

1

0

N

1

N

E

C

T

O

R

PUMP START
CONTACTOR

MANUAL
OVERRIDE/
LIFT DOWN

VALVE

TO
BATTERY

F

O

C

PUMP/MOTOR
ASSEMBLY

CIRCUIT BREAKER PANEL

DUMP
VALVE

POT-HOLE

LIMIT

SWITCHES

Figure 3-4. Overview of VP UL-EE Approved Optional Electrical System. (Sheet 1 of 2)

BOX

5

0

1

X

M

O

R

N

R

O

T

C

E

N

3-10 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

TO

TERMINAL

BATTERY

TERMINAL

CONTROLLER BOX

LAPTOP COMPUTER

at X105 port on the MC-1 controller box

Requires P/N-2900868 Configuration Kit.)

X104

X101

X105

X103

(remove existing connector

and plug-in the laptop computer.

TILT
SENSOR
SWITCH

USE WIRING

DIAGRAM

FIGURE 3-3.

THIS SECTION

OF THE

MANUAL WITH

THIS PICTORIAL

WIRING DIAGRAM

ELEVATION

LIMIT

SWITCH

F

R

O

M

X

1

0

C

O

1

N

N

E

C

T

O

R

BATTERY

CHARGER

CUTOUT

SWITCH

TO

PLATFORM

CONTROL

BOX

BATTERY

+

TO

5

0

1

R

X

O

M

T

O

C

R

E

F

N

N

O

C

GROUND

CONTROLS

SWITCH

(LIFT UP/LIFT DOWN)

GROUND

CONTROLS

RELAY

EXTERNAL

DRIVE/HORN

RELAY

CONTACTOR

RELAY

PLATFORM

CONTROLLER

MC-1

BRAKE

RELEASE

WIRING

BRAKE

RELEASE

DRIVE MOTOR

POWER LEADS

WIRING

MOTOR/BRAKE

ASSEMBLY

(LEFT SIDE)

BRAKE LIMIT

SWITCH

WIRING

MOTOR/BRAKE

Figure 3-4. Overview of VP UL-EE Approved Optional Electrical System. (Sheet 2 of 2)

DRIVE MOTOR

POWER LEADS

ASSEMBLY

(RIGHT SIDE)

3120728 – JLG Lift – 3-11

SECTION 3 - TROUBLESHOOTING

SHO

RX DO

TX DO

LIFT UP

LIFT DOWN

X101
B+
B+ CONTROL
MAIN POWER DISCONNECT
ELEVATION SWITCH
TILT CUTOUT
CHARGER INTERLOCK

B–

X102
B+
EMERGENCY STOP
CAN-LO
CAN-HI
CENTER DETECT
B–
EMERGENCY STOP

X103 – LEFT MOTOR
MOTOR 1
MOTOR 2
BRAKE 1
BRAKE2

PIN

A1

3
5
1
2
4

A2

PIN

15
14
13

5
6
1
7

PIN

A1
A2

5
3

X104 – RIGHT MOTOR
MOTOR 1
MOTOR 2
BRAKE 1
BRAKE 2

PINS USED FO R
COMMUNICATION
TO SERIAL PORT
ON LAPTOP OR PC.

X105

GROUND

PIN

7
8

13

4

6
PUMP CONTACTOR
DRIVE CUTOUT
BRAKE STATUS
HORN
ALARMS
HOURMETER

5

12
11
15
14

3

PIN

A1
A2

5
2

HORN
RELAY

X105 X101 X104

X102 X103

END VIEW OF MC-1 BOX

WING X CONNECTOR LOCATION

Figure 3-5. VP Electrical Diagram. (with UL-EE Approved Option)

3-12 – JLG Lift – 3120728

MOTION
ALARM
BREAKER

SECTION 3 - TROUBLESHOOTING

POWER

RELAY

PUMP FUSE

PUMP VALVES

BREAKER

TILT BEAKER

BEACON BRKR.

KEY SWITCH BREAKER

Figure 3-5 VP Electrical Diagram. (with UL-EE Approved Option)

4933134_A

3120728 – JLG Lift – 3-13

SECTION 3 - TROUBLESHOOTING

CYLINDER

PRES.
COMPENSATED
FLOW VALVE

EXTEND TUBE

SOLENOID
TWO POSITION/TWO
WAY DUMP VALVE

FILTER/
SCREEN

RETURN TUBE

SOLENOID
WITH
MANUAL
OVERRIDE

FILTER/SCREEN

CHECK
VALVE

ADJ. RELIEF
VALVE

PUMP ENDHEAD

MOTOR

TANK

Figure 3-6. Hydraulic Diagram. (VP Series)

3-14 – JLG Lift – 3120728

PUMP

FILTER/SCREEN

1282953

SECTION 3 - TROUBLESHOOTING

3.5 TROUBLESHOOTING SECTION - TABLE OF CONTENTS

OHM RATINGS FOR VARIOUS COMPONENTS PAGE

Ohm Ratings for Various Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16

MAIN POWER CIRCUIT TROUBLESHOOTING

Unit Will Not Power Up From Ground Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

No Power At Platform Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18

DRIVE TRAIN TROUBLESHOOTING

Won’t Drive (Platform Lowered Or Elevated) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

Won’t Drive (Platform Elevated Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22

Won’t Climb Grade. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24

Drives In Opposite Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25

Will Only Drive A Short Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26

Won’t Drive Straight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28

Noise From Drive Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29

MAST TROUBLESHOOTING

Platform Will Not Lift Up Using Platform Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30

Platform Will Not Lower Using Platform Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33

Platform Will Not Lift Up From Ground Control Toggle Switch . . . . . . . . . . . . . . . . . . . . . . . . . 3-34

Platform Will Not Lower From Ground Control Toggle Switch . . . . . . . . . . . . . . . . . . . . . . . . . 3-35

Platform Will Not Lower Manually . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36

Platform Lift Up And Down Jerky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-37

Mast Noisy When Lifting And Lowering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38

Platform (Mast) Won’t Stay Elevated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39

Platform (Mast) Descends Too Slowly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

HYDRAULIC LEAK TROUBLESHOOTING

Miscellaneous Hydraulic Leak Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-41

BASE FRAME COMPONENTS TROUBLESHOOTING

Caster Wheels Not Operating Freely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

Pot Hole Protection (PHP) Bars Will Not Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42

3120728 – JLG Lift – 3-15

SECTION 3 - TROUBLESHOOTING

3.6 OHM RATINGS FOR VARIOUS COMPONENTS

The following table contains ohm ratings for various VP Series machine components.

Table 3-3. Ohm Ratings for Various Components

COMPONENT NOMINAL RESISTANCE @ TEMPERATURE RESISTANCE RANGE POSSIBLE

Main Contactor 46.8ohm - 57.2ohm @ 68deg F 35.7ohm - 67.3ohm

Pump Motor 0.2ohm - 0.4ohm @ 77deg F 0.12ohm - 0.49ohm

Pump Relay 16.0ohm - 17.6ohm @ 77deg F 9.9ohm - 21.8ohm

Brake Coil 44.7ohm - 52ohm @ 68deg F 31.4ohm - 65.3ohm

Drive Motor (Bodine) .1 to .3ohm

(Can change depending on the rotation of the

armature and temperature.)

N/A

3-16 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

3.7 MAIN POWER CIRCUIT TROUBLESHOOTING

Unit Will Not Power Up From Ground Control

Overview Of Procedure

The following procedure tests the circuits from the Battery (+) terminal through the Ground Control Box and to the Main
Contactor Relay and Main Contactor for 24 volts or more. Also the Lift Up/Down Relay circuit is tested.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Battery connections clean and tight.

• Key switch positioned to Ground (GRND) control.

• Emergency stop switch pulled out. (Reset Position)

Table 3-4. Unit will not Power Up From Ground Control.

STEP ACTION SPEC YES NO

1. Check the 5 amp inline fuse on the Red 1-1 wi re from the battery (+)
terminal to the ground control box, key switch.
(Under pump/motor cover).

Ground Control Box Assembly (Disassembled)

2. Is there 24 volts or more reading at the key switch, terminal B.

3. C he c k fo r 2 4 v o l ts o r m o re o n t he Ye l/ Re d , 2- 7 wi re f ro m th e k e y

switch to the E-stop switch.

4. Check for 24 volts or more on the Yel/Red, 2-8 wire from the E-stop
to the Ground Control Relay, terminal 86.

5. Check for 24 volts or more on the Yel/Red, 2-4 wire from the E-stop
to the Main Contactor Relay, terminal 87.

Main Contactor Circuit

6. Check for 24 volts or more on the Yel/Red, 2-4 wire from the Main
Contactor Relay, terminal 87 to the Main Contactor.

7. Did Main Contactor close? — Go to Step 9 Go to Step 8

8. Is the Black ground wire connection from the Main Contactor to

ground OK?

9. At this point, 24 volts should be present at the following terminal
points; • Terminal 86 on the Ground Control Relay.

• Main Contactor, Yel/Red, 2-4 wire.

10. With Main Contactor engaged, 24 volts or more should be present at
the following terminal points;

• Pump Motor - 21’ cable #1.

• Yel/Red, 2-6 wire on the Pump Contactor.

• Yel/Red, 2-6 wires on the Lift Up/Down Relay.

24 volts OK, go to Step 2 Replace Fuse

Check Wiring

2 4 v ol ts G o t o S te p 3

from Battery to

Te rm in a l B .

Repair or Replace

Repair wiring or

2 4 v ol ts G o t o S te p 4

Replace Key

Switch

Repair wiring or

— G o t o S te p 5

Replace E-Stop

Switch

Repair wiring or

— G o t o S te p 6

Replace E-Stop

Switch

Repair wiring or

— G o t o S te p 7

Repla ce Main

Contactor Relay

—

Replace Main

Contactor

Repair Ground

Wiring

———

———

3120728 – JLG Lift – 3-17

SECTION 3 - TROUBLESHOOTING

No Power At Platform Control

Overview Of Procedure

The following procedure checks voltage and ground starting from the power source (batteries) through the ground control
station (key switch/E-stop) to the MC-1 box and finally to the platform control.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Keyswitch is turned to PLAT. (Platform)

• Both Emergency Stop Switches Reset (Ground/Platform). (Out)

• Connection of X102 Cable from MC-1 box to Platform Control, secure on both ends.

Table 3-5. No Power At Platform Control.

STEP ACTION SPEC YES NO

1. Check if the inline 5 amp fuse is blown on the Red, 1-1 wire at the
ground control station. (Ground control cover must be removed)

2. Check voltage to the Yel/Red, 2-2 wire at the MC-1 box, X101 con­nector, pin 3.

3. Check for Ground to the Black wire at the MC-1 box, X101 connec­tor, pin A2.

4. Check voltage to the Yel/Red, 2-3 wire at the MC-1 box, X101 con­nector, pin 5.

5. Check voltage to the Yel/Red, 2-5 wire at the MC-1 box, X101 con­nector, pin A1.

6. Check voltage to the Yel/Red, 2-2 wire at the MC-1 box, X101 con­nector, pin 3, from the Power Relay pin 30.

7. Check voltage to the Power Relay, pin 87. 24 volts Go to Step 9 Go to Step 8

8. Check for Ground to the Power Relay on the Black wire pin 85, to

Ground.

9. Check voltage to the Yel/Red, 2-4 wire at the Main Contactor from
the Power Relay, pin 87.

10. Check for Ground, on the Black wire to the Main Contactor.

11. Check voltage at the Battery Cable from Battery to Main Contactor.

12. Check voltage to the Yel/Red, 2-5 wire at the Main Contactor.

— If OK, go to Step 2 Replace Fuse

Per form the E-

2 4 v ol ts G o t o S te p 3

Stop/Key Switch

Circuit Check

(Table 3-17)

Check connec-

Ground Go to Step 4

tion/wiring

between Battery

and X101, Pin A2

2 4 v ol ts G o t o S te p 5

Replace MC -1

Control Box

24 volts Go to Step 13 Go to Step 6

Check the wire

24 volts Go to Step7

between the

Pow er Relay a nd

Connection

Check wiring to

Ground Replac e Relay

Ground

Connection

24 volts Go to Step 10

Check the Yel/

Red, 2-4 Wiring

Check wiring to

Ground Go to Step 11

Ground

Connection

24 volts Go to Step 12

24 volts

Check Yel/Red 2-

5 Wire

Check Batter y

Cable

Repla ce Main

Contactor

3-18 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-5. No Power At Platform Control.

13. Check voltage on the Red/Blk wire at the MC-1 box, X102 connec-

tor, pin 15, to the Platform Control.

14. Check for Ground on the BRN wire at the MC-1 box, X102 connector,
pin 1, to the Platform Control.

15. Check voltage on the Red/Blk wire, pin 9 on the Platform Control
box.

16. Check for Ground on the BRN wire, pin 8 on the Platform Control
box.

24 volts Go to Step 14

Ground Go to Step 15

24 volts Go to Step 16 Replace Cable

Ground

Repla ce Plat form

Control

Replace MC -1

Box

Replace MC -1

Box

Replace Cable

3120728 – JLG Lift – 3-19

SECTION 3 - TROUBLESHOOTING

3.8 DRIVE TRAIN TROUBLESHOOTING

Won’t Drive (Platform Lowered Or Elevated)

IF MACHINE WON’T DRIVE ONLY WHEN PLATFORM IS ELEVATED, SEE SECTION 4.4

Overview Of Procedure

The following procedures check the components and circuits that feed data to the MC-1 Controller box assuring it is receiv­ing the proper signals and conditions before engaging the machines’ drive motors.

Check For These Obvious Conditions First:

• Joystick Powered On

• Unit will Lift & Lower Platform

• Machine is not Tilted - (3 LEDs flashing at joystick control)

• PHP Device is not Obstructed - (4 LEDs flashing at joystick control)

• Brakes are not Released - (2 LEDs flashing at joystick control)

• Charger is not Plugged In - (8 LEDs flashing at joystick control)

STEP ACTION SPEC YES NO

1. Check for ground from elevation limit switch in the X101 connector,
pin 1 (49-5) at MC-1 box.

Table 3-6. Won’t Drive. (Platform Lowered or Elevated)

Check Elevation

— G o t o S te p 2

Circuit (Table 3-7)

2. Check for ground from charger circuit wire in the X101 connector,
pin 4 (49-7) at MC-1 box. (Perform this check with the charger

— Faul ty Char ger Go to St ep 3

unplugged)

3. Check for ground from brake limit switches in the X105 connector,
p in 1 1 at M C - 1 b o x .

— G o t o S te p 4

Limit Switch Cir-

cuit (Table 3-8)

4. Check that brakes are releasing, (2 LEDs) when joystick is enabled
& moved forward.

—

Check Drive

Motor Circuit

Switch/Circuit

(Table 3-9)

Table 3-7. Elevation Switch Circuit Check

• Perform these checks at the elevation switch which is located inside the top of mast section-1.

• Check with mast lowered.

STEP ACTION SPEC YES NO

1. Check for ground into the switch from ground connection.

2. Check for ground out of switch to the 49-5 wire.

3. Check for ground from switch to X101, Pin 1.

— G o t o S te p 2

— G o t o S te p 3

——

Adjust/Replace

Repair Wire or

Limit Switch

Check Brake

Check Brake

(Table 3-10)

Repair

Connection

Switch

Connection

3-20 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-8. Brake Limit Switch Circuit Check

STEP ACTION SPEC YES NO

1. Check for ground into the switch from the ground connection on the
left brake limit switch.

2. Check for ground on the 49-4 wire coming out of left brake limit
switch.

3. Check for ground on the 49-4 wire going into the right brake limit
switch.

4. Check for gound on the 49-3 side of the right brake limit switch.

— G o t o S te p 2

— G o t o S te p 3

— G o t o S te p 4

—

Replace

MC-1 box

Repair

Connection

Adjust/Replace

Switch

Repair/Replace

49-4 wire

Repair wire or

Connection

Table 3-9. Drive Motor/Circuit Check

• Perform these checks with the joystick enabled and pushed to the full forward position.

STEP ACTION SPEC YES NO

1. Check for 24 volts at the drive motor on the 55-3 wire on the right
motor and the 55-7 wire on the left drive motor. (Positive Side)

2. Check for 24 volts at the 55-3 wi re at the X104 connector, p in A2 (for
r i g h t m o t o r ) a n d t h e 5 5 - 7 w ir e a t t h e X 10 3 c o n n e c to r , p i n A 1 ( f o r l e f t
motor).

Table 3-10. Brake Switch/Circuit Check

24 volts

24 volts

Prob lem wit h

Motor

Check wiring and

connections

Go the Step 2

Problem in MC-1

box or Joystick

• Perform these checks with the joystick enabled and pushed to the full forward position.

STEP ACTION SPEC YES NO

1. Check for 24 volts at the wiring con nectors on the 55-4 wire on the
right drive motor brake unit and the 55-8 wire on the left drive motor
brake unit.

2. Check for 24 volts at the 55-4 wire at the X104 connector, pin 5(for
right motor) and the 55-8 wire at the X103 connector, pin 5 (for left
motor).

24 volts

24 volts

Clean, Gap or

Replace Brake

Unit

Check wiring and

connections

Go to Step 2

Problem in MC-1

box or Joystick

3120728 – JLG Lift – 3-21

SECTION 3 - TROUBLESHOOTING

Won’t Drive (Platform Elevated Only)

Overview Of Procedure

The following procedures check the components and circuits that feed data to the MC-1 Controller box assuring it is receiv­ing the proper signals and conditions before engaging the machines’ drive motors.

Check For These Obvious Conditions First:

• Joystick Powered On

• Unit will Lift & Lower Platform

• Machine is not Tilted - (3 LEDs flashing at joystick control)

• PHP Device is not Obstructed - (4 LEDs flashing at joystick control)

• Brakes are not Released - (2 LEDs flashing at joystick control)

• Charger is not Plugged In - (8 LEDs flashing at joystick control)

Ta b l e 3 - 1 1 . W o n ’t Drive with Platform Elevated

STEP ACTION SPEC YES NO

1. C he c k fo r gr ou n d on t i lt c i rc u it at MC - 1 b o x , X 1 01 c on n ec to r, p in 2,
(O/R, 49-6 wire).

2. Check for ground on PHP circuit at MC-1 box, X105 connector, pin
12, (O/R, 49-1 wire).

— G o t o S te p 2

—

Prob lem in MC -1

controller box

Check Tilt Sensor

Circuit (Table 3-

12)

Check PHP

Switch Circuit

(Table 3-13)

Table 3-12. Tilt Sensor Circuit Check

• No ground at MC -1 box, X101 connector, pin 2, (O/R, 49-6 wire).

STEP ACTION SPEC YES NO

1. Is tilt sensor light on showing a tilt conditio n, even though machine is
within tilt limit.

2. Check for ground on the Black wire (di rect to ground) running into tilt
sensor. (Continuity to B-)

3. C h e ck f o r 2 4 v o lt s a t t h e G r ee n t o ( Y / R, 2 - 5 ) w i r e fr o m t h e m a in c o n ­tactor relay.

—

— G o t o S te p 3

— G o t o S te p 4

Adjust tilt sensor

if necessary

Go to Step 2

Connection

Check Connec-

tion to Main Con-

tactor Relay

4. Check for ground on the White to (O/R, 49-6) wire at connector.

—

Repair connec­tion at the X101
connector end/

broken wire O/R

Replace

Tilt Sensor

49-6

Repair

3-22 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-13. PHP Limit Switch Circuit

• No ground on PHP circuit at MC-1 box, X105 connector, pin 12, (O/R, 49-1 wire).

• With PHP bars up.

STEP ACTION SPEC YES NO

1. Check for ground on Black wire (direct to ground) on the right side
PHP limit switch. (Continuity to B –)

2. Check for ground on O/R, 49-2 wire to left PHP limit switch.

3. Ch ec k fo r g ro u nd on O /R , 4 9- 1 wi re to MC - 1 b ox , X 10 5 c on ne c to r,

pin 12.

— G o t o S te p 2

— G o t o S te p 3

Repair connec-

—

tion at the X105

connector end

Connection

Adjust/Replace

Right Switch

Adjust/Replace

Left Switch

Repair

3120728 – JLG Lift – 3-23

SECTION 3 - TROUBLESHOOTING

Won’t Climb Grade

Overview Of Procedure

The following procedure checks the drive motor and attached components for component failure, misadjustment due to
wear.

Check For These Obvious Conditions First:

• Batteries are Fully Charged (24 Volts)

• Speed Control is Set to Maximum

• Is Grade within the Maximum Allowable Specification of 15% Grade (8.5 degrees)

• Does the Travel Surface allow for Proper Drive Wheel Traction

• Is Platform Load within the Maximum Rated Capacity

Table 3-14. Won’t Climb Grade

STEP ACTION SPEC YES NO

1. Does machine drive straight on a level surface?

2. Are both the left and right drive motor, slip-clutches, located

between the drive motor and the drive wheels, working properly?

3. Do the left and right drive motor brakes release properly and allow
the drive wheels to rotate freely ?

4. Check the amperage output of the on the drive motor leads. They
should not exceed 70 amps while pulling a grade.

5. Check the condition of the drive motor brushes.

6. If all above is OK, Drive motors are working properly. Consult Fac-

tory.

— G o t o S te p 2

— G o t o S te p 3

— G o t o S te p 4

Controller will

—

Shut Drive Down

and will flash a 7

LED Code

— OK, go to Step 6

———

Refer to Machine

Won’t Drive

Straight

(Table 3-18)

Repair, Replace

or Adjust Slip

Clutch

Dragging?

Repair, Replace

or Adjust Brakes

Go to Step 5

Worn down,

replace brushes

or drive motor

3-24 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Drives In Opposite Direction

Overview Of Procedure

The following procedure checks that both the drive motor power wire connections correctly installed and are secure and
tight. Also that the joystick control assembly for proper installation at the platform control box.

Check For These Obvious Conditions First:

• If the Left Drive Motor (X103) connector is switched with the Right Drive Motor (X104) connector at the MC-1 box, you will
immediately get an 2 LED flashing Error Code at the Platform Control when the machine is powered up.

• Check Joystick Calibration (See Procedure in Service Manual, Section-2).

Table 3-15. Drives In Opposite Direction

STEP ACTION SPEC YES NO

1. Check the connection of the Orange, 55-3 wire to the right drive
motor at both ends;

• At the X104 connector on the MC-1 box, pin A1.

— G o t o S te p 2

• And the Black wire at the Drive Motor end.

2. Check the connection of the Orange, 55-6 wire to the right drive
motor at both ends;

• At the X104 connector on the MC-1 box, pin A2.

— G o t o S te p 3

• And the White wire at the Drive Motor end.

3. Check the connect ion of the Orange, 55 -7 wire to the lef t drive motor
at both ends;

• At the X103 connector on the MC-1 box, pin A1.

— G o t o S te p 4

• And the Black wire at the Drive Motor end.

4. Check the connection of the Orange, 55-10 wire to the left drive
motor at both ends;

• At the X103 connector on the MC-1 box, pin A2.

— G o t o S te p 5

• And the White wire at the Drive Motor end.

5. Is platform control box under warranty? ** — Order New One Go to Step 6

6. Internal to the platform control - check that the joystick assembly

inside the platform control has not been installed backwards.

7. Internal to the platform control - check that the joystick assembly
wiring to the platform control circuit card is not wired backwards.

—

—

Re-install
Correctly

Re-install
Correctly

* Repair or

Replace

Connection

* Repair or

Replace

Connection

* Repair or

Replace

Connection

* Repair or

Replace

Connection

Go to Step 7

Consult Factory

* Note: If the Orange, 55-3 or 55-6 wires to the right drive motor in the X104 connector or the Orange, 55-7 or 55-10 wires to

the left drive motor in the X103 connector at the MC-1 controller are crossed up that drive motor will run backwards.

** Note: If platform controller is not under warranty, the internal components of the platform controller are replaceable and

can be ordered and replaced seperately from the complete platform control box. See procedures in Section-2 of
this Service Manual for Joystick Assembly/ Disassembly.

3120728 – JLG Lift – 3-25

SECTION 3 - TROUBLESHOOTING

Will Only Drive A Short Distance

Overview Of Procedure

The following procedure will eliminate any problems found in the power circuit to the MC-1 controller box and also any
objectionable environmental conditions.

Check For These Obvious Conditions First:

• Is Battery Voltage 24 Volts? (Fully Charge Batteries)

Table 3-16. Only Drives A Short Distance

STEP ACTION SPEC YES NO

1. Is platform controller staying powered up when machine stops driv­ing?

— G o t o S te p 2

2. Check the voltage out of the X101 connector, pin 5, to the power
relay pin 86. Check continuity at pin 85. 24 Volts Go to Step 3

3. Check the voltage from pin 87 on the power relay to the main con­tactor. (Main contactor should be closed at this point)

24 Volts Go to Step 4

4. Check the voltage on the Yel/Red, 2-5 wire o n the X101 connector,
pin A1, from the main contactor. 24 Volts Go to Step 5

5. What type of surface is machine being operated on? Is surface sof t,
unstable or up a steep grade?

Machine will not

perform well on a

soft or unstable

surface, if motor

—

draw is over 70

amps, controller

machine down.

6. Are brakes releasing when trying to drive?

— G o t o S te p 7

7. Is drive system running free? No noise or dragging.

— G o t o S te p 8

8. Is machine being operated in an environment with high static

Machine may be

charge?

charge in the MC-

—

which will make

the drive system

will shut the

( 7 LED Code)

building static

1 controller,

shut down.

Check the E-Stop

& Key Switch

Circuit

(Table 3-17)

Repai r or Repla ce

Wires, or Problem

with MC-1 Box

Repai r or Repla ce

Wires or Relay

Repai r or Repla ce

Wires or Main

Contactor

Go to Step 6

Repair/Replace

or Adjust Drive

Brakes

(See Procedure in

Service Manual)

Repair/Replace

or Adjust Drive

System

(See Procedure in

Service Manual)

—

3-26 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-17. E-Stop and Key Switch Circuit Check

• Batteries Fully Charged. (24 Volts)

• Ground Control Key Switch set to the Platform or on Ground position and the Emergency Stop Switch Reset to ON.

STEP ACTION SPEC YES NO

1. KEY SET TO PLATFORM: Check voltage on the Yel/Red, 2-2 wire
from the emergency stop switch to MC-1 controller box, pin 3 in the
X101 connector and pin 30 on the Power Relay.

2. KEY SET TO GROUND: Check voltage on the Yel/Red, 2-4 wire com-
ing out of the ground control box assembly to pin 87 on the power
relay, and main contactor. Yel/Red 2-8 wire to pin 86 on the ground
relay.

3. Open the Ground Control Box Assembly (housing with key switch
and E-stop switch mounted inside) and check the voltage on the Yel/

Red, 2-1 wire leading into the emergency stop switch from the Key
switch.

4. Check voltage on the Red, 1-1 wire leading into the Key switch.

5. Check voltage and continuity through the 5 amp fuse moun ted inline

outside of the ground control box assembly, on the Red, 1-1 wire.

6. Check connection at battery. 24 Volts Circuit OK N/A

24 Volts Circuit is OK Go to Step 2

24 Volts Circuit is OK Go to Step 3

Repair connec-

24 Volts

24 Volts

24 Volts Go to Step 6

tion to or replace

E-Stop switch

Repair connec-

tion to or replace

key switch

Go to Step 3

Go to Step 4

Replace Fu se or

Fuse Hol der if

damaged

3120728 – JLG Lift – 3-27

SECTION 3 - TROUBLESHOOTING

Won’t Drive Straight

Overview Of Procedure

The following procedure examines the drive motor assembly weldments attaching the drive motors to the base frame. Also
internal components of the the drive motors, gear box and a check of the components between the gear box and the drive
wheels.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Nothing is lodged between one of the wheels and the base frame.

• A caster wheel on the front of the machine is seized up, creating resistance.

• Joystick properly calibrated per procedure in Section-2 of Service Manual.

Table 3-18. Won’t Drive Straight.

STEP ACTION SPEC YES NO

1. Check for the following on the drive assembly, drive attachment
weldment; is bent, has broken welds, or loose hardware.

2. Check for the fol lowing on the drive assembly, drive m otor mounting
plates; are bent, are square with drive weldments, or is hardware
loose?

3. Check for the following on the drive assembly, drive motor hard­ware; is hardware loose, flange bearing - bad/loose, slip clutch ­check torque settings or adjustment.

4. Check the left and right drive motor brakes for loose hardware & not
releasing properly.

5. Inside the drive motor gear box check if; the drive shaft is exces­sively loose & conditon of drive shaft bearings.
Are any gears broken or gear teeth excessively worn.

6. Is the electrical signal and amperage draw to the drive motors
equal?

7. Check the driv e motor brushes, do they need replaced?

8. Is t he X1 0 2 w ir in g h ar ne ss ( fro m p la tf or m co nt ol bo x t o M C -1 bo x)

damaged, check wiring harness visually and individual wires with
ohm meter.

9. Is joystick control defective?
If possible, swap out with another platform control.

10. Is MC-1 control box defective or connections not tight?
If possible, swap out with another MC-1 control box.

—

—

—

—

—

24 volts

15 amps

—

—

—

—

Repair/Replace/

Tighten weldment

Repair/Replace/

Tighten weldment

Repair/Replace/
Tighten compo-

nent

Tighten or Adjust

per procedure

in this

Service Manual

Repair/Replace
components per
procedure in this

Service Manual

Recheck Steps

1 thru 5

Replace per

procedure in this

Service Manual

Repai r or Rep lace

Harness as

Required

Repair/Replace

Platform control

Tighten Connec-

tions or Replace

MC-1 box

Go to Step 2

Go to Step 3

Go to Step 4

Go to Step 5

Go to Step 6

Go to Step 7

Go to Step 8

Go to Step 9

G o t o S te p 10

—

3-28 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Noise From Drive Assembly

Overview Of Procedure

The following procedure examines the drive motor assembly weldments attaching the drive motors to the base frame. Also
internal components of the the drive motors, gear box and a check of the components between the gear box and the drive
wheels.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Nothing is lodged between one of the wheels and the base frame.

• A caster wheel on the front of the machine is seized up, creating resistance.

Table 3-19. Noise from Drive Assembly.

STEP ACTION SPEC YES NO

1. Check for the following on the drive assembly, drive attachment
weldment; is bent, has broken welds, or loose hardware.

2. Check for the fol lowing on the drive assembly, drive m otor mounting
plates; are bent, are square with drive weldments, or is hardware
loose?

3. Check for the following on the drive assembly, drive motor hard­ware; is hardware loose, flange bearing - bad/loose, slip clutch ­check torque settings or adjustment .

4. Check the left and right drive motor brakes for loose hardware & not
releasing properly.

5. Inside the drive motor gear box check if; the drive shaft is exces­sively loose & conditon of drive shaft bearings.
Are any gears broken or gear teeth excessively worn.

6. Is the electrical signal and amperage draw to the drive motors
equal?

7. Check the driv e motor brushes, do they need replaced?

—

—

—

—

—

24 volts

15 amps

—

Repair/Replace/

Tighten weldment

Repair/Replace/

Tighten weldment

Repair/Replace/

Tighten

Component

Tighten or Adjust

per procedure

in this

Service Manual

Repair/Replace

components per

procedure in this

Service Manual

Recheck Steps

1 thru 5

Replace per

procedure in this

Service Manual

Go to Step 2

Go to Step 3

Go to Step 4

Go to Step 5

Go to Step 6

Go to Step 7

—

3120728 – JLG Lift – 3-29

SECTION 3 - TROUBLESHOOTING

3.9 MAST TROUBLESHOOTING

Platform Will Not Lift Up Using Platform Control

Overview Of Procedure

This procedure examines the complete pump motor, ground control and pump valves electrical circuits.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Platform loaded within maximum allowable capacity.

• Hydraulic oil is within it’s specified operating temperature range.

Table 3-20. Platform Will Not Lift Up Using Platform Control.

STEP ACTION SPEC YES NO

1. Will platform lift from ground control switch?
Note: Key switch must be set to GRND to test this.

2. Does pump motor run?

3. Are the down and dump valves opening/closing properly?

Note: If machine will not lift and hydraulic oil is visible flowing in the
hydraulic tank, the dump valve is stuck in the open position.

4. Is the pressure set properly on the pump?

5. Is the lift cylinder OK?

6. Are the mast sections operating freely?

— Go to Step 2 See (Figure 3-24)

See Pump Circuit

— G o t o S te p 3

(Table 3-21 )

See Pump Valves

— G o t o S te p 4

Circuit Check

(Table 3-22 )

Set to correct

— G o t o S te p 5

pressure specifi-

cation per this

Service Manual

— G o t o S te p 6

—

Consult

Factory

Replace Lif t Cyl.

Check

Rebuild or

Check Mast,

Rebuild

if Necessary

3-30 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Table 3-21. Pump Circuit

• Battery voltage 24 volts. (Fully charge batteries)

• Key switch set to Platform .

STEP ACTION SPEC YES NO

1. At the pump motor, check for 24 volts at both ends of the battery
cable running from the main contactor to the pump case stud. (left
side)

PUMP CONTACTOR RELAY CIRCUIT

2. Check the connection of the ground cable (attached to 5/16" stud,
l e f t s i de ) t o t h e p um p c o n t a c to r , i s t i g h t a nd c o n n e c t ed o n o t h e r en d
to B- at the right side battery.

3. Check the connection of the ground cable (other side) is tight and
connected to the pump case stud (center).

4. Check the Yel/Red, 2-6 wire connected to the positive post on the
pump case for tightness and 24 volt reading.

5. Check the Tan, 55-1 wire connected to both the Ground control
switch and the MC-1 box, X105 connector, pin 5 through the pump
contactor relay. Without any lif t functions activated, it sho uld show
24 volts, with a lift function activated it should show ground.

DUMP VALVE CIRCUIT

6. C he c k th e Ye l/ R ed , 2- 6 w ir e co nn ec te d t o t he p o si t i ve ( + ) p o st o n
the pump case for 24 volts.

7. Check the Tan, 3-1 wire connected to both the Ground control
switch and the MC-1 box, X105 connector, pin 4 through the lift up
valve. Without any lift function activated, it should show 24 volts,
with a lift function activated it should show ground.

DOWN VALVE CIRCUIT

8. C he c k th e Ye l/ R ed , 2- 6 w ir e co nn ec te d t o t he p o si t i ve ( + ) p o st o n
the pump case for 24 volts.

9. Check the Tan, 4-1 wire connected to both the Ground control
switch and the MC-1 box, X105 connector, pin 6 through the lift
down valve. With out any lift functions, it should show 24 volts, with
a lift function it should show ground.

MAIN CONTACTOR CIRCUIT

10. Check the battery cable from the B+ (left side) battery for 24 volts.

11. Check the batter y cable going out to the pump case (left side) stud

for 24 volts.

12. Check the Yel/Red, 2-5 (1 0 ga.) wire to the MC -1 box, X101 connec­tor, pin A1 for 24 volts.

13. Check the Yel/Red, 2-4 wire to the Power Relay, pin #87 for 24
volts.

2 4 v ol ts G o t o S te p 2

Ground Go to Step 3

Ground Go to Step 4

2 4 v ol ts G o t o S te p 5

Ground Go to Step 6

2 4 v ol ts G o t o S te p 7

2 4 v ol ts G o t o S te p 8

2 4 v ol ts G o t o S te p 9

24 volts Go to Step 10

24 volts Go to Step 11

24 volts Go to Step 12

24 volts Go to Step 13

24 volts Go to Step 14

Tighten
Connection or
Replace Cable

if Necessary

Tighten
Connection or
Replace Cable

if Necessary

Tighten
Connection or
Replace Cable

if Necessary

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

3120728 – JLG Lift – 3-31

SECTION 3 - TROUBLESHOOTING

Table 3-21. Pump Circuit

14. Check the Black to ground on the pump contactor.

POWER RELAY CIRCUIT

15. Check the Yel/Red, 2-4 wire, #87 on the Power Relay to the main
contactor, and to diode at E-Stop for 24 volts.
N ot e: Po w er wi l l st o p at d io de , s il ve r l in e s ho u l d b e a wa y f ro m th e E ­Stop.

16. Check the Yel/Red, 2-2 wire, #30 on the Power Relay to the E-stop
a nd t o th e M C -1 b o x, X 1 01 c o nn e ct o r pi n 3 , f o r 24 v o lt s .

17. Check the Black, #85 pin on the Power Relay for connection to
ground at pump contactor.

18. Check the Yel/Red, 2-3 wire, #86 on the Power Relay to the MC-1
box, X101 connector pin 5, for 24 volts when the platform control is
powered up.

Table 3-22. Pump Valves Circuit

• Battery voltage 24 volts. (Fully charge batteries)

• Set key switch to Platform and set the Emergency Stop Button to the RESET position.

• Do wn Va lv e sh ou l d b e n or ma l ( cl os ed ).

• Dump Valve (up) should be normal (open).

• If machine will not lift and hydraulic oil is visible flowing in the hydraulic tank, the dump valve is stuck open.

Ground Go to Step 15

24 volts Go to Step 16

24 volts Go to Step 17

Ground Go to Step

— Go to Step

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

Tighten/Repair

Connection

STEP ACTION SPEC YES NO

LIFT UP - (CONDITIONS WHEN PUMP MOTOR IS RUNNING)

1. Pump Contactor Coil: Yel/Red, 2-6 wire - 24 volts
Tan, 55-1 wire - Ground

2. Lift Up Valve Coil : Yel/Red, 2-6 wire - 24 volts

Tan, 3-1 wire - Ground

L IF T UP - ( CH EC K W HE N PU M P MO T O R I S N OT R U NN I N G)

3. Pump Contactor Coil: Yel/Red, 2-6 wire - 24 volts
Tan, 55-1 wire - 24 volts

4. Lift Up Valve Coil : Yel/Red, 2-6 wire - 24 volts

Tan, 3-1 wire - 24 volts

LIFT DOWN - (CHECK WHEN DOWN AND ENABLE PADS ARE PUSHED ON THE PLATFORM CONTROL)

5. Lift Down Valve Coil:Yel/Red, 2-6 wire - 24 volts

Tan, 4-1 wire - Ground

LIFT DOWN - (CHECK WHEN NO FUNCTION AR E ENABLED ON THE PLATFORM CONTROL)

6. Lift Down Valve Coil:Yel/Red, 2-6 wire - 24 volts

Tan, 4-1 wire - 24 volts

———

———

———

———

———

———

3-32 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Platform Will Not Lower Using Platform Control

Overview Of Procedure

This procedure tests for ground coming out of the MC-1 box to the dump valve circuit and through to the ground control tog­gle switch.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Hydraulic oil is within it’s specified operating temperature range.

Table 3-23. Platform Will Not Lower Using Platform Control.

STEP ACTION SPEC YES NO

1. Will machine lower manually, using the manual descent knob? — Go to Step 2 See (Table 3-26)

2. Will machine lower from ground control switch?

Note: Key switch must be set to GRND to check this.

3. C he c k fo r gr ou nd o n t h e Tan , 4 -1 w i re a t t h e M C - 1 b o x , X 1 0 5 c o n ­nector, pin 6.

4. Check for ground on the Tan, 4-1 wire at the lift down coil.

5. Check complete pump motor circuit . (See Table 3-21) ———

— Go to Step 3 See (Table 3-23)

Repair/Replace

— G o t o S te p 4

Joystick/

MC-1 Box

Replace/Repair

— G o t o S te p 5

Wire or

Connection

3120728 – JLG Lift – 3-33

SECTION 3 - TROUBLESHOOTING

Platform Will Not Lift Up From Ground Control Toggle Switch

Overview Of Procedure

The following procedure examines the complete ground control circuit from the battery all the way to the pump motor for
wiring or components which could be causing a failure of that circuit.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Battery connections clean and tight.

• Key switch positioned to Ground (GRND) control.

• Emergency stop switch pulled out. (Reset Position)

• Ground control power supply and wiring, OK (Table 3-4).

• Manual descent valve closed.

• 5 amp fuses on power and pump circuits, OK.

• Hydraulic oil level, OK.

• Weight in platform does not exceed machine maximum capacity.

Table 3-24. Unit Will Not Lift Up From Ground Control Toggle Switch.

STEP ACTION SPEC YES NO

1. Does the pump motor r un when lift up is selected at the ground con­trol switch?

Note: Steps 2 th ru 9 are to be per formed with LIFT UP s elected at the
ground control.

2. Check terminal 30 and 85 on the ground control relay for ground. Is
ground contact OK?

3. Check continuity across terminals 87 and 30 on the ground control
relay. Is there continuity? (Relay must be energized)

4. Check the Black wire from terminal 87 on the ground control relay to
the lift up/down ground control switch. Is there continuity with B –?

5. Check for continuity across the terminals (Black to Tan 3-1 and Tan
55-1) of the lif t up/down ground control toggle switch. Is there con­tinuity?

6. Check the Tan, 3-1 wire for continuity from the lif t up/down ground
switch to the lift up coil. Is there continuity?

7. Check the Tan, 55-1 wire from the lift up/down ground switch to the
pump contactor for continuity. Is there continuity?

8. Check the Yel/Red, 2-6 wire from the pump motor to the pump con­tactor and lift-up coil for voltage. Is there voltage?

9. Check the wire from the lift switch (Tan 55-1) pump contactor to the
battery (-) terminal for continuity. Is there continuity?

10. Check the pump motor pressure relief setting. Is it within specifica­tion per Service Manual?

—

Go to Steps 5,6

and 10

Ground Go to Step 3

— Go to Step 4 Replace Relay

— G o t o S te p 5

— G o t o S te p 6

— G o t o S te p 7

— G o t o S te p 8

24 Volts Go to Step 9

——

— Set as Required

Check Ground

Pow er Ci rcui t

(Table 3-4)

Before Continu-

ing to Step 3

Repair Wiring or

Connection

Repair Wiring or

Connection

Replace Lift Up/

Down Ground

Control Switch

Repair Wiring or

Connection

Repair Wiring or

Connection

Repair Wiring or

Connection

Repair Wiring or

Connection

3-34 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Platform Will Not Lower From Ground Control Toggle Switch

Overview Of Procedure

The following procedure examines the complete ground control circuit from the battery all the way to the pump motor for
wiring or components which could be causing a failure of that circuit.

Check For These Obvious Conditions First:

• Battery voltage 24 volts. (Fully charge batteries)

• Battery connections clean and tight.

• Key switch positioned to Ground (GRND) control.

• Emergency stop switch set to the Reset position)

• Ground control power supply and wiring, OK (Table 3-4).

• 5 amp fuses on power and pump circuits, OK.

• Hydraulic oil level, OK.

Table 3-25. Unit Will Not Lower From Ground Control Toggle Switch.

STEP ACTION SPEC YES NO

1. Will machine lower manually? — Go to Step 3 Go to Step 2

2. Check for obstr uctions in the mast , cylinder, hydraulic lines and lif t

down valve.

3. Check terminal 30 and 85 on the ground control relay for ground. Is
ground contact OK? Continuity with B–.

4. Check continuity across terminals 87 and 30 on the ground control
relay. Is there continuity? (Relay must be energized)

5. Check the Black wire from terminal 87 on the ground control relay to
the lift up/down ground control switch. Is there continuity with B –?

6. Check for continuity across the ter minals (Black to Tan, 4-1 wire) of
the lift up/down ground control toggle switch. Is there continuity
with the switch activated?

7. Check the Tan, 4-1 wire for continuity from the lif t up/down ground
switch to the lift-down coil. Is there continuity?

8. Check the Yel/Red, 2-6 wire from the pump motor to the lift-down
coil for voltage. Is there voltage?

—

Ground Go to Step 4

Ground Go to Step 5 Replace Relay

— G o t o S te p 6

— G o t o S te p 7

— G o t o S te p 7

24 volts —

Repair, Rep lace

or Adjust

Go to Step 3

Repair Wiring or

Connection

Repair Wiring or

Connection

Replace Lift Up/

Down Ground

Control Switch

Repair Wiring or

Connection

Repair Wiring or

Connection

3120728 – JLG Lift – 3-35

SECTION 3 - TROUBLESHOOTING

Platform Will Not Lower Manually

Overview Of Procedure

The following procedure suggests components on the machine which might attribute to problems with the manual descent
circuit.

Table 3-26. Platform Will Not Lower Manually.

STEP ACTION SPEC YES NO

1. Check manual override solenoid with manual override (knob open). Go to Step 2 Open

2. Check Steps 1 thru 6 of ( Table 3-30) Repair Go to Step 3

3. Place the maximum capacity of weight in the Platform.

Does it Lower?

— Consult Factory

3-36 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Platform Lift Up And Down Jerky

Overview Of Procedure

The following procedure suggests areas on the machine which might attribute to erratic movement of the platform during lift
up and down.

Check For These Obvious Conditions First:

• If mast is not running smooth or has tight and rough spots, refer to the Mast Section Rebuild.

• Hydraulic oil level in reservoir tank at full level.

• Hydraulic oil no milky (presence of water), or not foamy (full of air).

Table 3-27. Platform Lift Up and Down Jerky.

STEP ACTION SPEC YES NO

CONTROLS (ELECTRICAL)

1. Is platform control, enable, up or down pad defective or worn out? — Replace pad Go to Step 2

2. Loose connections , ground and power.

—

3. Valve coils or solenoids keep opening and closing.

—

4. Problem internal to the MC-1 control box. — Replace box Go to Step 5

HYDRAULIC

5. Are the hydraulic valves working properly. — Replace Valve Go to Step 6

6. Pump drive cavitates. — Replace Pump Go to Step 7

7. Lift cylinder

—

Repair

connection

Repair Connec-

tion or Replace

Valve

Rebuild or

Replace Cylinder

Go to Step 3

Go to Step 4

—

3120728 – JLG Lift – 3-37

SECTION 3 - TROUBLESHOOTING

Mast Noisy When Lifting And Lowering

Overview Of Procedure

This procedure examines components of the mast itself and as well as it’s lifting components for dirt, debris, proper lubrica­tion and operation.

STEP ACTION SPEC YES NO

1. Do slide pads and slide pad channels need to be cleaned of dust,
dirt, or other debris?

2. Do chain/cables need to be lubricated per JLG specification in the
Service Manual?

3. Are the chain/cable sheave wheels dry and need lubrication?
Note: Plastic wheels will howl on the sheave pin when they are dr y.
Sheave wheels may seize to the sheave pin and the pin may turn in
the pin retainer blocks.

Table 3-28. Mast Noisy when Lifting and Lowering.

—

—

—

Clean Pads and

Channels

Lubricate as

Required

Lubricate or

Replace Sheave

Pins and Wheels

4. Are the sequence cables (located on the side of mast) chattering
when the springs are compressed?
Note: This noise is normal at the sequence cable sheave wheels
when the mast is completely lowered. However if the sequence
cable chattering is happening no matter what position the mast is in,
it could be a result of the mast being shimmed to tight or dir t and

—

Clean Slide Pads/

Channels or Re-

shim Mast per

Service Manual

debris in the slide pad channels causing the mast to be tight.

5. Is the bore of the lif t cylinder dry?

6. Are the bearings in the lift pump motor and pump drive worn?

7. Are the hydraulic lines vibrating together?

8. Check if the pump motor is loose to it’s mounting plate.

—

—

—

—

Replace Packing

or Lift Cylinder

Repai r or Rep lace

Pump

Adjust the Posi­tion of the Lines

Tighten pump

mounting

fasteners

9. Hydraulic oil could be cavatating inside the pump.

—

Repair or Repla ce

Pump

Go to Step 2

Go to Step 3

Go to Step 4

Go to Step 5

Go to Step 6

Go to Step 7

Go to Step 8

Go to Step 9

—

3-38 – JLG Lift – 3120728

SECTION 3 - TROUBLESHOOTING

Platform (Mast) Won’t Stay Elevated

Overview Of Procedure

The following procedure requests that the lift down, dump, and pump internal valves be checked to see if any are stuck
open, it also examines the lift down and dump valve circuits. Also suggests that the lift cylinder packing could be leaking
internally.

Check For These Obvious Conditions First:

• Manual descent valve is closed tight.

Table 3-29. Platform (Mast) Won’t Stay Elevated.

STEP ACTION SPEC YES NO

1. Is the lift down valve stuck open?

—

2. Check the valve inside the pump, it could be stuck open. — Replace Pump Go to Step 3

3. Lift down valves could be open due to incorrect electrical signal.

—

4. Dump valve could be open due to incorrect electrical signal.

—

5. Oil could be passing around the lift cylinder bore packing.

—

Repair or Clean

Valve

Check Pump

Valve Electrical

Circuit

(Table 3-22)

Check Pump

Valve Electrical

Circuit

(Table 3-22)

Replace or

Rebuild the Lif t

Cylinder

Go to Step 2

Go to Step 4

Go to Step 5

—

3120728 – JLG Lift – 3-39

SECTION 3 - TROUBLESHOOTING

Platform (Mast) Descends Too Slowly

Overview Of Procedure

The following procedure examines the mast some hydraulic components for obstructions and defects.

Table 3-30. Platform (Mast) Descends Too Slowly.

STEP ACTION SPEC YES NO

1. Check mast slide pads shimmed to tight. — Reshim Mast Go to Step 2

2. Is there an obstruction in the mast?

3. The lift cylinder packing could be too tight in the bore of the cylinder

barrel.

4. Check the flow valve on the extend hydraulic line for a restriction, i.e.
dirt.

5. Check if the lift down valve is opening completely.

6. Is there a restricted hydraulic line (smashed)?

—

—

—

—

—

Remove

Obstruction

Rebuild or

Replace Cylinder

Clean or Replace

Flow Valve

Clean or Replace

Valve

Replace Hydrau-

lic Line

Go to Step 3

Go to Step 4

Go to Step 5

Go to Step 6

—

3-40 – JLG Lift – 3120728