JLG 260MRT Service Manual

Service & Maintenance Manual

Model

260MRT

3121801

April 19, 2013

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

SECTION A. INTRODUCTION - MAINTENANCE SAFETY

PRECAUTIONS

AGENERAL

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 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
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 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.

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

B HYDRAULIC SYSTEM SAFETY

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

Relieve system pressure by cycling the applicable
control several times with the engine stopped and
ignition on, to direct any line pressure back into the
reservoir. Pressure feed lines to system components
can then be disconnected with minimal fluid loss.

CMAINTENANCE

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

• NO SMOKING IS MANDATORY. NEVER REFUEL DUR­ING ELECTRICAL STORMS. ENSURE THAT FUEL CAP
IS CLOSED AND SECURE AT ALL OTHER TIMES.

• 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 WARNINGS AND CAU­TIONS ON MACHINE AND IN SERVICE MANUAL.

• KEEP OIL, GREASE, WATER, ETC. WIPED FROM
STANDING SURFACES AND HAND HOLDS.

• USE CAUTION WHEN CHECKING A HOT, PRESSUR­IZED COOLANT SYSTEM.

• NEVER WORK UNDER AN ELEVATED BOOM UNTIL
BOOM HAS BEEN SAFELY RESTRAINED FROM ANY
MOVEMENT BY BLOCKING OR OVERHEAD SLING, OR
BOOM SAFETY PROP HAS BEEN ENGAGED.

• 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.

REVISION LOG

3121801 – JLG Lift – a

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

Original Issue - April 13, 2000

Revised - January 24, 2002

Revised - April 22, 2004

Revised - July 3, 2006

Revised - August 30, 2006

Revised - October 11, 2007

Revised - April 28, 2008

Revised - December 19, 2008

Revised - October 20, 2011

Revised - April 19, 2013

b – JLG Lift – 3121801

TABLE OF CONTENTS

TABLE OF CONTENTS

SUBJECT - SECTION, PARAGRAPH PAGE NO.

SECTION A - INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

A.A General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-a

A.B Hydraulic System Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-a

A.C Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-a

SECTION 1 - SPECIFICATIONS

1.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.2 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.3 Component Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1.4 Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

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

1.6 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.7 Pressure Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.8 Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.9 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.10 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.11 Serial Number Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

SECTION 2 - PROCEDURES

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

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

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

2.4 Cylinders - Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

2.5 Valves - Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.6 Component Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.7 Wear Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.8 Cylinder Checking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

2.9 Lift Cylinder Removal and Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.10 Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.11 Steer Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2.12 Limit Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

2.13 Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

2.14 Drive Pump Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-21

2.15 Automatic Choke - Field Adjustment (DF-750) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

2.16 Joystick Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2.17 Tilt Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-25

2.18 Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

2.19 Electronic Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-29

2.20 Flash Codes and Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-33

2.21 Machine Model Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-39

2.22 Machine Configuration Programming Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-40

2.23 Preventive Maintenance and Inspection Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41

SECTION 3 - GENERAL ELECTRICAL INFORMATION & SCHEMATICS

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

3.2 Multimeter Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

3.3 Applying Silicone Dielectric Compound To Amp Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

3.4 Working With Deutsch Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3.5 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

3.6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

3121801 – JLG Lift – i

TABLE OF CONTENTS

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

1-1. Serial Number Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1-2. Lubrication Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

1-3. Operating Temperature Specifications - Kubota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1-4. Torque Chart - (In/Lb - Ft/Lb). (For ASTM Fasteners) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

1-5. Torque Chart (Metric Conversion) - (For ASTM Fasteners) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8

1-6. Torque Chart - (N, m) - (For Metric Class Fasteners). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-9

2-1. Arms and Platform Positioning and Support, Cylinder Repair. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-2. Lift Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-3. Cylinder Barrel Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-4. Capscrew Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-5. Cylinder Rod Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-6. Tapered Bushing Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-7. Rod Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2-8. Wiper Seal Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

2-9. Installation of Head Seal Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

2-10. Piston Seal Kit Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2-11. Tapered Bushing Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2-12. Seating the Tapered Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2-13. Poly-Pak Piston Seal Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-14. Rod Assembly Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-15. Steer Cylinder Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

2-16. Leveling Jack Assembly - (Prior to S/N 105371) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-17

2-17. Leveling Jack Assembly - (S/N 105371to S/N 141689) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-18

2-18. Leveling Jack Assembly - (S/N 141689 to Present) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

2-19. Valve Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2-20. Automatic Choke Adjustment (DF-750) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

2-21. Joystick Controller - (JLG P/N 1600308) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2-22. Joystick Controller - (JLG P/N 1600403) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-24

2-23. Tilt Sensor Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2-24. Tilt Sensor Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-25

2-25. Tilt Sensor Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

2-26. Tilt Sensor Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-26

2-27. Hand Held Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-29

2-28. Analyzer Flow Chart - Sheet 1 of 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

2-29. Analyzer Flow Chart - Sheet 2 of 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-36

2-30. Analyzer Flow Chart - Sheet 3 of 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37

2-31. Analyzer Flow Chart - Sheet 4 of 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38

3-1. Voltage Measurement (DC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2

3-2. Resistance Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

3-3. Continuity Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

3-4. Current Measurement (DC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

3-5. AMP Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

3-6. Connector Assembly (1 of 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

3-7. Connector Assembly (2 of 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

3-8. Connector Assembly (3 of 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

3-9. Connector Assembly (4 of 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

3-10. Connector Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

3-11. Connector Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9

3-12. DT/DTP Contact Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

3-13. DT/DTP Contact Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3-14. HD/HDP Contact Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3-15. HD/HDP Locking Contacts Into Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-16. HD/HDP Contact Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

3-17. HD/HDP Unlocking Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

. .3-11

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TABLE OF CONTENTS

3-18. Electrical Schematic - Sheet 1 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22

3-19. Electrical Schematic - Sheet 2 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23

3-20. Electrical Schematic - Sheet 3 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

3-21. Electrical Schematic - (w/ Generator) - Sheet 1 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

3-22. Electrical Schematic - (w/ Generator) - Sheet 2 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27

3-23. Electrical Schematic - (w/ Generator) - Sheet 3 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-28

3-24. Electrical Componants Installation - Prior to S/N 141689 - Sheet 1 . . . . . . . . . . . . . . . . . . . . . . . .3-30

3-25. Electrical Componants Installation - Prior to S/N 141689 - Sheet 2 . . . . . . . . . . . . . . . . . . . . . . . .3-31

3-26. Electrical Componants Installation - S/N 141689 to Present - Sheet 1 . . . . . . . . . . . . . . . . . . . . .3-32

3-27. Electrical Componants Installation - S/N 141689 to Present - Sheet 2 . . . . . . . . . . . . . . . . . . . . .3-33

3-28. Hydraulic Schematic - Prior to S/N 141689 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34

3-29. Hydraulic Schematic - S/N 141689 to Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-35

3-30. Hydraulic Diagram (Generator). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-36

3-31. Hydraulic Diagram (Leveling Jacks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-37

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1-1 Operating Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-2 Capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-3 WG750-B Kubota Gasoline/LP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-4 D905-B Kubota Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-5 D1005 Kubota Diesel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

1-6 Tire Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1-7 Pump Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1-8 Hydraulic Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1-9 Lubrication Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1-10 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-11 Pressure Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-12 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-13 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1-14 Lubrication Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

2-1 Cylinder Component Torque Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

2-2 Holding Valve Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-3 Joystick Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2-4 Joystick Plug Loading Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2-5 Joystick Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-24

2-6 Joystick Plug Loading Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2-7 Tilt Sensor Harness Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2-8 Tilt Sensor Harness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

2-9 Help Messages and Flash Codes - Software P1.X. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-33

2-10 Machine Model Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-39

2-11 Machine Configuration Programming Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-40

2-12 Preventive Maintenance and Safety Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42

3-1 Elevation System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

3-2 Chassis Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16

3-3 Hydraulic System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

3-4 Electrical System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

3121801 – JLG Lift – iii

TABLE OF CONTENTS

This page left blank intentionally.

iv – JLG Lift – 3121801

SECTION 1. SPECIFICATIONS

1.1 SPECIFICATIONS 1.2 CAPACITIES

Table 1-1. Operating Specifications

Machine Weight 3701 kg (8160 lbs)

Machine Height:
Fully Elevated
Stowed

Machine Width 1.8 m (5.9 f t)

Machine Length 2.7 m (8.9 ft)

Platform Railing Height 1.1 m (43.5 in.)

Platform Dimensions 2.59 x 1.65 m (8.5 x 5. 4 ft)

Platform Capacity 570 kg (1250 lbs)

Platform Extension Capacity 140 kg (300 lbs)

Max Travel Speed 4.5 kmh (2.8 mph)

Max Travel Grade 35%

Max Slope:
Side to Side
Fore & Aft

Tu rn in g R ad iu s:
Inside
Outside

Lift Speed:
Up
Down

Max Tire Load 921 kg (3300 lbs)

Max Ground Bearing Pressure 3.2 kg/cm² (33 psi)

Max Hydraulic system Pressure 20.68 Mpa (3000 psi)

El ectr ical Syst em Vol tage 12 Volt

Wheelbase 2 m (78 in.)

Ground Clearance 20.3 cm (8 in.)

Max Windspeed 12.5 m/s (28 mph)

Max Horizontal Manual Side Force 400 N (90 lbf)

Number of Persons 2

8 m (26 ft)

2.3 m (7.5 ft)

3°
5°

2.1 m (6.9 ft)

4.4 m (14.4 ft)

32 - 34 sec

21 - 27 secs

Fuel Tank 27.2 L (7.2 gal)

Hydraulic Oil Tank 56.8 L (15 gal)

Hydraulic System (including tank) 68.1 L (18 gal)

Engine Crankcase:
Gasoline Engine
Diesel Engine

Engine Coolant:
Gasoline Engine
Diesel Engine

1.3 COMPONENT DATA

Engine

Table 1-3. WG750-B Kubota Gasoline/LP

Type 3 cylinder, liquid-cooled

Power 24.5 horsepower @ 3600 rpm

Idle 1500 rpm

High Engine 3600 rpm

Alternator 40 Amp

Fuel Consumption:
Low RPM
High RPM

Type 3 cylinder, liquid-cooled

Power 26 horsepower @ 3000 rpm

Low Idle 800 rpm

High Engine 3800 rpm

Alternator 40 Amp

Fuel Consumption:
Low RPM
High RPM

Table 1-2. Capacities

Table 1-4. D905-B Kubota Diesel

Table 1-5. D1005 Kubota Diesel

SECTION 1 - SPECIFICATIONS

3.25 L (3.4 qts)
4 L (4.2 qts)

4.7 L (1.25 gal)

5.7 L (1.5 gal)

4.9 Lph (1.3 gph)
9 Lph (2.4 gph)

2.6 Lph (0.68 gph)

5.5 Lph (1.48 gph)

Type 3 cylinder, liquid-cooled

Power 23.5 horsepower @ 3000 rpm

Bore x Stroke 76.0 mm x 73.6 mm

Displacement

Low Idle 800 rpm

High Idle 3800 rpm

Alternator 12V, 30 Amp

Star ter 12V, 1.0 Amp

61.08 in

3

3121801 – JLG Lift – 1-1

SECTION 1 - SPECIFICATIONS

Tires

Table 1-6. Tire Specifications

Description (Standard) (Non-Marking)

Size 26x12-15

Load Range 8 Ply

Pressure 55 psi

Pumps

Table 1-7. Pump Specifications

Description Drive Pump Lift/Steer Pump

Ty pe P is to n G ea r

Max Output

Displacement

83.3 lpm (22 gpm) @
3000 rpm

28 cm³/rev

(1.7 in³/rev)

18 lpm (4.75 gpm) @

3000 rpm

1.4 cm³/rev

(0.36 in.³/rev)

Steer/Drive System

Tire - Pneumatic or foam filled - 26 x 12 15 lug

NOTE: Inflate pneumatic tire to 3.1 bar (45 psi)

Toe-In - Adjust to 12.7 mm (1/2 inch) overall

Drive Motor - Rexroth

1.4 LUBRICATION

Hydraulic Oil

NOTE: 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.

Table 1-8. Hydraulic Oil

HYDRAULIC SYSTEM OPERATING

TEMPERATURE RANGE

-18 to -5°C

(0 to +23°F)

-18 to +100°C
(0 to +210°F)

+10 to +100°C

(+50 to +210°F)

NOTE: 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.

SAE VISCOSITY GRADE

10W

10W-20,10W-30

20W-20

1.5 LUBRICATION SPECIFICATIONS

Table 1-9. Lubrication Specifications

Hydraulic Filter - Inline

Full flow paper filter (Cartridge type)

Torque Requirement

All wheel lug nuts should be torqued to 142 Nm (105 ft lb)
every 150 hours.

NOTE: When maintenance becomes necessary or a fas-

tener has loosened, refer to the Torque Chart in this
section to determine proper torque value.

1-2 – JLG Lift – 3121801

KEY SPECIFICATIONS

Multipurpose Grease having a minimum dripping

MPG

EPGL

EO

HO

point of 350 degrees F. Excellent water resistance

and adhesive qualities, and being of extreme pres-

sure type. (Timken OK 40 pounds minimum.)

Extreme Pressure Gear Lube (oil) meeting API ser-

vice classification GL-5 or MIL-Spec MIL-L-2105.

Engine (crankcase) Oil. Gas - API SF/SG class,

MIL- L-2 10 4. D ie se l - AP I C C/ CD cl a ss , M IL- L-

2104B/MIL-L-2104C.

Hydraulic Oil. API service classification GL-3, e.g.

Mobil 424.

SECTION 1 - SPECIFICATIONS

1.6 CYLINDER SPECIFICATIONS

Table 1-10. Cylinder Specifications

Description Bore Stroke Rod Dia.

Lift Cylinder

Steer Cylinder

10.2 cm
(4 in.)

5.1 cm
(2 in.)

119.4 cm
(47 in.)

20 cm

(7.84 in.)

6.4 cm

(2.5 in.)

2.8 cm

(1.12 in.)

1.7 PRESSURE SETTINGS

Table 1-11. Pressure Settings

Main Relief (±3.4 bar/50 psi) 227.5 bar (3300 psi)

Steer Relief - Left 158.8 bar (2300 psi)

Steer Relief - Right 117.2 bar (1700 psi)

Lift Up Relief 158.8 bar (2300 psi)

Leveling Jack Relief 207 bar (2500 psi)

1.8 LIMIT SWITCHES

The machine is equipped with the following limit switches:

Tilt Alarm - Illuminates a light on the platform and sounds
an alarm when the machine is 3° out of level side to side
or 5° fore and aft.

Platform Overload - When platform becomes overloaded,
the LED on the platform controller illuminates and the lift
up and drive functions are cut out. Platform is overloaded
with 652 kg (1437.5 lbs).

High Drive Cut-Out - High drive speed is cut out when the
platform is raised above the stowed position.

Max Drive Height - The drive function is cut out when the
platform is raised by 2.3 - 2.4 m (7.5 - 8 ft).

1.9 MAJOR COMPONENT WEIGHTS

Table 1-12. Major Component Weights

Component Weight

Platform

Platform and Extension

Manual Platform Extension

Arm Assembly (Includes Lift Cylinder)

Chassis - w/Standard Tires

295 kg

(650 lbs)

454 kg

(1000 lbs)

159 kg

(350 lbs)

925 kg

(2040 lbs)

1869 kg

(4120 lbs)

1.10 CRITICAL STABILITY WEIGHTS

DO NOT REPLACE ITEMS CRITICAL TO STABILITY, SUCH AS
ENGINES, AXLES OR TIRES, WITH ITEMS OF DIFFERENT
WEIGHT OR SPECIFICATION. DO NOT MODIFY UNIT IN ANY WAY
TO AFFECT STABILITY.

Table 1-13. Critical Stability Weights

Component Weight

Tire and Wheel Assembly - Std (each)

T ir e an d W he e l A s se m b ly - FF ( e ac h )

Kubota Gas/DF Engine (Dr y)

Kubota Diesel Engine (Dry)

23 kg

(50 lbs)

69 kg

(152 lbs)

61.7 kg

(136 lbs)

42 kg

(93 lbs)

3121801 – JLG Lift – 1-3

SECTION 1 - SPECIFICATIONS

Figure 1-1. Serial Number Location

1.11 SERIAL NUMBER LOCATIONS

For machine identification, a serial number plate is affixed
to the machine. The plate is located on the rear center of
the machine frame, just below the middle step of the lad­der. In addition, if the serial number plate is damaged or
missing, the machine serial number is stamped on the
right front frame rail, adjacent to the sizzor arms.

1-4 – JLG Lift – 3121801

SECTION 1 - SPECIFICATIONS

Figure 1-2. Lubrication Diagram

Table 1-14. Lubrication Chart

INDEX NO COMPONENT NUMBER/TYPE LUBE POINTS LUBE METHOD

INTERVAL

HOURS

1 Hydraulic Oil Reservoir Fill Cap/Drain Plug

HO - Check HO Level

HO - Change HO

10/500

2 Hydraulic Filter Element N/A Initial Change - 50 Hours 250

3

Engine Crankcase,

Engine Oil Filter,

Engine Fuel Filter,

Engine Fuel Filter (Kubota DF752)

Fill Cap/Drain Plug,

Filter Element,
Filter Element,

Filter Element

Check Engine Oil Level,

Initial Change - 50 Hours,

Check & Clean every 100 hrs,

Check & Clean every 100 hrs

10/100,

200,
400,

Yea rly

4Rail Slides N/A MPG - Brush100

KEY TO LUBRICANTS:

MPG - Multi-purpose Grease

EPGL - Extreme Pressure Gear Lube

HO - Hydraulic Oil (Mobil 424)

TO AVOID PERSONAL INJURY, USE SAFETY PROP FOR ALL
MAINTENANCE REQUIRING PLATFORM TO BE ELEVATED.

NOTE: Be sure to lubricate like items on each side

Recommended lubricating intervals are based on
machine operations under normal conditions. For

machines used in multi-shift operations and/or
exposed to hostile environments or conditions,
lubrication frequencies must be increased accord­ingly.

NOTE: Operate hydraulic functions through one complete

cycle before checking hydraulic oil level in tank. Oil
should be visible in ADD sight window on hydraulic
tank. If oil is not visible, add oil until oil is visible in
both ADD and FULL sight windows on tank. Do not
overfill tank.

Any time the pump coupling is removed, coat
splines of coupling with Texaco Code 1912 grease
prior to assembly.

3121801 – JLG Lift – 1-5

SECTION 1 - SPECIFICATIONS

4150548_E

Figure 1-3. Operating Temperature Specifications - Kubota

1-6 – JLG Lift – 3121801

SECTION 1 - SPECIFICATIONS

REFERENCE JLG ANEROBIC THREAD LOCKING COMPOUND

JLG P/N Loctite® P/N ND Industries P/N

Description

0100011

242

TM

Vibra-TITE

TM

121

Medium Strength (Blue)

0100019

271

TM

Vibra-TITE

TM

140

High Strength (Red)

0100071

262

TM

Vibra-TITE

TM

131

Medium - High Strength (Red)

Size TPI Bolt Dia

Tensile

Stress Area

Clamp Load

In Sq In LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]

4 40 0.1120 0.00604 380 8 0.9 6 0.7

48 0.1120 0.00661 420 9 1.0 7 0.8

6 32 0.1380 0.00909 580 16 1.8 12 1.4

40 0.1380 0.01015 610 18 2.0 13 1.5

8 32 0.1640 0.01400 900 30 3.4 22 2.5

36 0.1640 0.01474 940 31 3.5 23 2.6

10 24 0.1900 0.01750 1120 43 4.8 32 3.5

32 0.1900 0.02000 1285 49 5.5 36 4

1/4 20 0.2500 0.0318 2020 96 10.8 75 9 105 12

28 0.2500 0.0364 2320 120 13.5 86 10 135 15

In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]

5/16 18 0.3125 0.0524 3340 17 23 13 18 19 26 16 22

24 0.3125 0.0580 3700 19 26 14 19 21 29 17 23

3/8 16 0.3750 0.0775 4940 30 41 23 31 35 48 28 38

24 0.3750 0.0878 5600 35 47 25 34 40 54 32 43

7/16 14 0.4375 0.1063 6800 50 68 35 47 55 75 45 61

20 0.4375 0.1187 7550 55 75 40 54 60 82 50 68

1/2 13 0.5000 0.1419 9050 75 102 55 75 85 116 68 92

20 0.5000 0.1599 10700 90 122 65 88 100 136 80 108

9/16 12 0.5625 0.1820 11600 110 149 80 108 120 163 98 133

18 0.5625 0.2030 12950 120 163 90 122 135 184 109 148

5/8 11 0.6250 0.2260 14400 150 203 110 149 165 224 135 183

18 0.6250 0.2560 16300 170 230 130 176 190 258 153 207

3/4 10 0.7500 0.3340 21300 260 353 200 271 285 388 240 325

16 0.7500 0.3730 23800 300 407 220 298 330 449 268 363

7/8 9 0.8750 0.4620 29400 430 583 320 434 475 646 386 523

14 0.8750 0.5090 32400 470 637 350 475 520 707 425 576

1 8 1.0000 0.6060 38600 640 868 480 651 675 918 579 785

12 1.0000 0.6630 42200 700 949 530 719 735 1000 633 858

1 1/8 7 1.1250 0.7630 42300 800 1085 600 813 840 1142 714 968

12 1.1250 0.8560 47500 880 1193 660 895 925 1258 802 1087

1 1/4 7 1.2500 0.9690 53800 1120 1518 840 1139 1175 1598 1009 1368

12 1.2500 1.0730 59600 1240 1681 920 1247 1300 1768 1118 1516

1 3/8 6 1.3750 1.1550 64100 1460 1979 1100 1491 1525 2074 1322 1792

12 1.3750 1.3150 73000 1680 2278 1260 1708 1750 2380 1506 2042

1 1/2 6 1.5000 1.4050 78000 1940 2630 1460 1979 2025 2754 1755 2379

12 1.5000 1.5800 87700 2200 2983 1640 2224 2300 3128 1974 2676

NO. 5000059 REV. J

Values for Zinc Yellow Chromate Fasteners (Ref 4150707)

SAE GRADE 5 BOLTS & GRADE 2 NUTS

Torque

(Dry)

Torque

(Loctite® 262

TM

or Vibra-

TITE

TM

131)

Torque

Lubricated

Torque

(Loctite® 242

TM

or 271

TM

OR Vibra-TIT E

TM

111 or

140)

3. * ASSEMBLY USES HARDENED WASHER

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT METHODS TOLERANCE = ±10%

1.12 TORQUE CHARTS

Figure 1-4. Torque Chart (SAE Fasteners - Sheet 1 of 7)

3121801 – JLG Lift – 1-7

SECTION 1 - SPECIFICATIONS

Size TPI Bolt Dia

Tensile

Stress Area

Clamp Load

In Sq In

4 40 0.1120 0.00604

48 0.1120 0.00661

6 32 0.1380 0.00909

40 0.1380 0.01015

8 32 0.1640 0.01400

36 0.1640 0.01474

10 24 0.1900 0.01750

32 0.1900 0.02000

1/4 20 0.2500 0.0318

28 0.2500 0.0364

In Sq In

5/16 18 0.3125 0.0524

24 0.3125 0.0580

3/8 16 0.3750 0.0775

24 0.3750 0.0878

7/16 14 0.4375 0.1063

20 0.4375 0.1187

1/2 13 0.5000 0.1419

20 0.5000 0.1599

9/16 12 0.5625 0.1820

18 0.5625 0.2030

5/8 11 0.6250 0.2260

18 0.6250 0.2560

3/4 10 0.7500 0.3340

16 0.7500 0.3730

7/8 9 0.8750 0.4620

14 0.8750 0.5090

1 8 1.0000 0.6060

12 1.0000 0.6630

1 1/8 7 1.1250 0.7630

12 1.1250 0.8560

1 1/4 7 1.2500 0.9690

12 1.2500 1.0730

1 3/8 6 1.3750 1.1550

12 1.3750 1.3150

1 1/2 6 1.5000 1.4050

12 1.5000 1.5800

NO. 5000059 REV. J

3. * ASSEMBLY USES HARDENED WASHER

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

2. ALL TORQUE VA LUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT METHODS TOLERANCE = ±10%

LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]

1320 43 5
1580 60 7
1800 68 8
2860 143 16 129 15
3280 164 19 148 17

LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m

4720 25 35 20 25 20 25
5220 25 35 25 35 20 25
7000456040 553550
7900 50 70 45 60 35 50

9550 70 95 65 90 50 70
10700 80 110 70 95 60 80
12750 105 145 95 130 80 110
14400 120 165 110 150 90 120
16400 155 210 140 190 115 155
18250 170 230 155 210 130 175
20350 210 285 190 260 160 220
23000 240 325 215 290 180 245
30100 375 510 340 460 280 380
33600 420 570 380 515 315 430
41600 605 825 545 740 455 620
45800 670 910 600 815 500 680
51500 860 1170 770 1045 645 875
59700 995 1355 895 1215 745 1015
68700 1290 1755 1160 1580 965 1310
77000 1445 1965 1300 1770 1085 1475

87200 1815 2470 1635 2225 1365 1855

96600 2015 2740 1810 2460 1510 2055

104000 2385 3245 2145 2915 1785 2430

118100 2705 3680 2435 3310 2030 2760
126500 3165 4305 2845 3870 2370 3225
142200 3555 4835 3200 4350 2665 3625

Torque

(Loctite® 242

TM

or 271

TM

OR Vibra-TITE

TM

111 or

140) K=.18

Torque

(Loctite® 262

TM

or Vibra-

TITE

TM

131)

K=0.15

SAE GRADE 8 (HEX HD) BOLTS & GRADE 8 NUTS*

Torque

(Dry or Loctite® 263)

K= 0.20

1-8 – JLG Lift – 3121801

Figure 1-5. Torque Chart (SAE Fasteners - Sheet 2 of 7))

Size TPI Bolt Dia

Tensile

Stress Area

Clamp Load

See Note 4

In Sq In LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]

4 40 0.1120 0.00604

48 0.1120 0.00661

6 32 0.1380 0.00909

40 0.1380 0.01015

8 32 0.1640 0.01400

36 0.1640 0.01474

10 24 0.1900 0.01750

32 0.1900 0.02000

1/4 20 0.2500 0.0318 2860 122 14 114 13

28 0.2500 0.0364 3280 139 16 131 15

In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]

5/16 18 0.3125 0.0524 4720 20 25 20 25 20 25

24 0.3125 0.0580 5220 25 35 20 25 20 25

3/8 16 0.3750 0.0775 7000 35 50 35 50 35 50

24 0.3750 0.0878 7900 40 55 40 55 35 50

7/16 14 0.4375 0.1063 9550 60 80 55 75 50 70

20 0.4375 0.1187 10700 65 90 60 80 60 80

1/2 13 0.5000 0.1419 12750 90 120 85 115 80 110

20 0.5000 0.1599 14400 100 135 95 130 90 120

9/16 12 0.5625 0.1820 16400 130 175 125 170 115 155

18 0.5625 0.2030 18250 145 195 135 185 130 175

5/8 11 0.6250 0.2260 20350 180 245 170 230 160 220

18 0.6250 0.2560 23000 205 280 190 260 180 245

3/4 10 0.7500 0.3340 30100 320 435 300 410 280 380

16 0.7500 0.3730 33600 355 485 335 455 315 430

7/8 9 0.8750 0.4620 41600 515 700 485 660 455 620

14 0.8750 0.5090 45800 570 775 535 730 500 680

1 8 1.0000 0.6060 51500 730 995 685 930 645 875

12 1.0000 0.6630 59700 845 1150 795 1080 745 1015

1 1/8 7 1.1250 0.7630 68700 1095 1490 1030 1400 965 1310

12 1.1250 0.8560 77000 1225 1665 1155 1570 1085 1475

1 1/4 7 1.2500 0.9690 87200 1545 2100 1455 1980 1365 1855

12 1.2500 1.0730 96600 1710 2325 1610 2190 1510 2055

1 3/8 6 1.3750 1.1550 104000 2025 2755 1905 2590 1785 2430

12 1.3750 1.3150 118100 2300 3130 2165 2945 2030 2760

1 1/2 6 1.5000 1.4050 126500 2690 3660 2530 3440 2370 3225

12 1.5000 1.5800 142200 3020 4105 2845 3870 2665 3625

NO. 5000059 REV. J

4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT REPRESENT FULL STRENGTH

CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED, ADDITIONAL TESTING IS REQUIRED.

SOCKET HEAD CAP SCREWS

Magni Coating (Ref 4150701)*

Torque

(Dry) K = .17

Torque

(Loctite® 242

TM

or 271

TM

OR Vibra-TITE

TM

111 or

140 OR Precoat 85®

K=0.16

Torque

(Loctite® 262

TM

or Vibra-

TITE

TM

131)

K=0.15

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT METHODS TOL ERANCE = ±10%

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLA TED FASTENERS

*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED STEEL OR RAW AL UMINUM

SECTION 1 - SPECIFICATIONS

3121801 – JLG Lift – 1-9

Figure 1-6. Torque Chart (SAE Fasteners - Sheet 3 of 7)

SECTION 1 - SPECIFICATIONS

Size TPI Bolt Dia

Tensile

Stress Area

Clamp Load

See Note 4

In Sq In LB IN-LB [N.m] IN-LB [N.m] IN-LB [N.m]

4 40 0.1120 0.00604

48 0.1120 0.00661

6 32 0.1380 0.00909

40 0.1380 0.01015

8 32 0.1640 0.01400

36 0.1640 0.01474

10 24 0.1900 0.01750

32 0.1900 0.02000

1/4 20 0.2500 0.0318 2860 143 16 129 15

28 0.2500 0.0364 3280 164 19 148 17

In Sq In LB FT-LB [N.m] FT-LB [N.m] FT-LB [N.m]

5/16 18 0.3125 0.0524 4720 25 35 20 25 20 25

24 0.3125 0.0580 5220 25 35 25 35 20 25

3/8 16 0.3750 0.0775 7000 45 60 40 55 35 50

24 0.3750 0.0878 7900 50 70 45 60 35 50

7/16 14 0.4375 0.1063 9550 70 95 65 90 50 70

20 0.4375 0.1187 10700 80 110 70 95 60 80

1/2 13 0.5000 0.1419 12750 105 145 95 130 80 110

20 0.5000 0.1599 14400 120 165 110 150 90 120

9/16 12 0.5625 0.1820 16400 155 210 140 190 115 155

18 0.5625 0.2030 18250 170 230 155 210 130 175

5/8 11 0.6250 0.2260 20350 210 285 190 260 160 220

18 0.6250 0.2560 23000 240 325 215 290 180 245

3/4 10 0.7500 0.3340 30100 375 510 340 460 280 380

16 0.7500 0.3730 33600 420 570 380 515 315 430

7/8 9 0.8750 0.4620 41600 605 825 545 740 455 620

14 0.8750 0.5090 45800 670 910 600 815 500 680

1 8 1.0000 0.6060 51500 860 1170 775 1055 645 875

12 1.0000 0.6630 59700 995 1355 895 1215 745 1015

1 1/8 7 1.1250 0.7630 68700 1290 1755 1160 1580 965 1310

12 1.1250 0.8560 77000 1445 1965 1300 1770 1085 1475

1 1/4 7 1.2500 0.9690 87200 1815 2470 1635 2225 1365 1855

12 1.2500 1.0730 96600 2015 2740 1810 2460 1510 2055

1 3/8 6 1.3750 1.1550 104000 2385 3245 2145 2915 1785 2430

12 1.3750 1.3150 118100 2705 3680 2435 3310 2030 2760

1 1/2 6 1.5000 1.4050 126500 3165 4305 2845 3870 2370 3225

12 1.5000 1.5800 142200 3555 4835 3200 4350 2665 3625

NO. 5000059 REV. J

4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT REPRESENT FULL STRENGTH

CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED, ADDITIONAL TESTING IS REQUIRED.

SOCKET HEAD CAP SCREWS

Torque

(Dry)

K = .20

Torque

(Loctite® 242TM or 271

TM

OR Vibra-TITE

TM

111 or

140 OR Precoat 85®

K=0.18

Zinc Yellow Chromate Fasteners (Ref 4150707)*

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT METHODS TOLERANCE = ±10%

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

*3. ASSEMBLY USES HARDENED WASHER OR F ASTENER IS PLACED AGAINST PLATED STEEL OR RAW ALUMINUM

Torque

(Loctite® 262

TM

or Vibra-

TITE

TM

131)

K=0.15

1-10 – JLG Lift – 3121801

Figure 1-7. Torque Chart (SAE Fasteners - Sheet 4 of 7)

SECTION 1 - SPECIFICATIONS

Size PITCH

Tensile

Stress

Area

Clamp

Load

Torque

(Dry or Loctite®

263

TM

)

Torque

(Lub)

Torque

(Loctite® 262

TM

OR Vibra-

TITE

TM

131)

Torque

(Loctite®

242

TM

or 271

TM

OR Vibra-

TITE

TM

111 or

140)

Sq mm KN [N.m] [N.m] [N.m] [N.m]

3 0.5 5.03 2.19 1.3 1.0 1.2 1.4

3.5 0.6 6.78 2.95 2.1 1.6 1.9 2.3
4 0.7 8.78 3.82 3.1 2.3 2.8 3.4
5 0.8 14.20 6.18 6.2 4.6 5.6 6.8
6 1 20.10 8.74 11 7.9 9.4 12
7 1 28.90 12.6 18 13 16 19
8 1.25 36.60 15.9 26 19 23 28

10 1.5 58.00 25.2 50 38 45 55
12 1.75 84.30 36.7 88 66 79 97
14 2 115 50.0 140 105 126 154

16 2 157 68.3

219 164 197 241
18 2.5 192 83.5 301 226 271 331
20 2.5 245 106.5 426 320 383 469
22 2.5 303 132.0 581 436 523 639
24 3 353 153.5 737 553 663 811
27 3 459 199.5 1080 810 970 1130
30 3.5 561 244.0 1460 1100 1320 1530
33 3.5 694 302.0 1990 1490 1790 2090
36 4 817 355.5 2560 1920 2300 2690
42 4.5 1120 487.0 4090 3070 3680 4290

4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT
REPRESENT FULL STRENGTH CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED,
ADDITIONAL TESTING IS REQUIRED.

*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGA INST PLATED
STEEL OR RAW ALUMINUM

CLASS 8.8 METRIC BOLTS

CLASS 8 METRIC NUTS

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT
METHODS TOLERANCE = ±10%

NO. 5000059 REV. J

Figure 1-8. Torque Chart (METRIC Fasteners - Sheet 5 of 7))

3121801 – JLG Lift – 1-11

SECTION 1 - SPECIFICATIONS

Size PITCH

Tensile

Stress

Area

Clamp

Load

Torque

(Dry or Loctite®

263

TM

)

K = 0.20

Torque

(Lub OR Loctite®

242

TM

or 271TM OR

Vibra-TITE

TM

111 or

140)

K= 0.18

Torque

(Loctite® 262

TM

OR

Vibra-TITE

TM

131)

K=0.15

Sq mm KN [N.m] [N.m] [N.m]

3 0.5 5.03 3.13

3.5 0.6 6.78 4.22
4 0.7 8.78 5.47
5 0.8 14.20 8.85
6 1 20.10 12.5
7 1 28.90 18.0 25.2 22.7 18.9
8 1.25 36.60 22.8 36.5 32.8 27.4

10 1.5 58.00 36.1 70 65 55
12 1.75 84.30 52.5 125 115 95
14 2 115 71.6 200 180 150

16 2 157 97.8

315 280 235
18 2.5 192 119.5 430 385 325
20 2.5 245 152.5 610 550 460
22 2.5 303 189.0 830 750 625
24 3 353 222.0 1065 960 800
27 3 459 286.0 1545 1390 1160
30 3.5 561 349.5 2095 1885 1575
33 3.5 694 432.5 2855 2570 2140
36 4 817 509.0 3665 3300 2750
42 4.5 1120 698.0 5865 5275 4395

CLASS 10.9 METRIC BOLTS

CLASS 10 METRIC NUTS

CLASS 12.9 SOCKET HEAD CAP SCREWS M3 - M5*

4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT

REPRESENT FULL STRENGTH CAPABILI TY OF SHCS. IF HIGHER LOAD IS REQUIRED,

ADDITIONAL TESTING IS REQUIRED.

*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED
STEEL OR RAW ALUMINUM

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT
METHODS TOLERANCE = ±10%

NO. 5000059 REV. J

Figure 1-9. Torque Chart (METRIC Fasteners - Sheet 6 of 7)

1-12 – JLG Lift – 3121801

SECTION 1 - SPECIFICATIONS

Size PITCH

Tensile

Stress

Area

Clamp Load

See Note 4

Torque

(Dry or Loctite®

263

TM

)

K = .17

Torque

(Lub OR Loctite®

242

TM

or 271

TM

OR Vibra-TITE

TM

111 or 140)

K = .16

Torque

(Loctite® 262

TM

OR Vibra-TITE

TM

131)

K = .15

Sq mm kN [N.m] [N.m] [N.m]

30.55.03

3.5 0.6 6.78

40.78.78

50.814.20

6120.1012.5 13 12 11

7128.9018.0 21 20 19

8 1.25 36.60 22.8 31 29 27
10 1.5 58.00 36.1 61 58 54
12 1.75 84.30 52.5 105 100 95
14 2 115 71.6 170 160 150

16 2 157

97.8 265 250 235
18 2.5 192 119.5 365 345 325
20 2.5 245 152.5 520 490 460
22 2.5 303 189.0 705 665 625
24 3 353 220.0 900 845 790
27 3 459 286.0 1315 1235 1160
30 3.5 561 349.5 1780 1680 1575
33 3.5 694 432.5 2425 2285 2140
36 4 817 509.0 3115 2930 2750
42 4.5 1120 698.0 4985 4690 4395

CLASS 12.9 SOCKET HEAD CAP SCREWS

M6 AND ABOVE*

4. CLAMP LOAD LISTED FOR SHCS IS SAME AS GRADE 8 OR CLASS 10.9 AND DOES NOT

REPRESENT FULL STRENG TH CAPABILITY OF SHCS. IF HIGHER LOAD IS REQUIRED,

ADDITIONAL TESTING IS REQUIRED.

*3. ASSEMBLY USES HARDENED WASHER OR FASTENER IS PLACED AGAINST PLATED
STEEL OR RAW ALUMINUM

NOTES: 1. THESE TORQUE VALUES DO NOT APPLY TO CADMIUM PLATED FASTENERS

2. ALL TORQUE VALUES ARE STATIC TORQUE MEASURED PER STANDARD AUDIT
METHODS TOLERANCE = ±10%

NO. 5000059 REV. J

Magni Coating (Ref 4150701)*

3121801 – JLG Lift – 1-13

Figure 1-10. Torque Chart (METRIC Fasteners - Sheet 7 of 7)

SECTION 1 - SPECIFICATIONS

NOTES:

1-14 – JLG Lift – 3121801

SECTION 2. PROCEDURES

SECTION 2 - PROCEDURES

2.1 GENERAL

This section provides information necessary to perform
maintenance on the scissor 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.

The maintenance procedures included consist of servic­ing and component removal and installation, disassembly
and assembly, inspection, lubrication and cleaning. Infor­mation on any special tools or test equipment is also pro­vided where applicable.

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.

Safety and Workmanship

Your safety, and that of others, is the first consideration
when engaging in the maintenance of equipment. Always
be conscious of 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.

Cleanliness

1. 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 air, fuel, and oil supplies clean; however, these
items must be maintained on a scheduled basis in
order to function properly.

2. At any time when air, fuel, or oil lines are discon­nected, clear adjacent areas as well as the openings
and fittings themselves. As soon as a line or compo-

nent is disconnected, cap or cover all openings to
prevent entry of foreign matter.

3. 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

4. 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.

5. 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°.

6. 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

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

1. 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.

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

3. If a 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.

3121801 – JLG Lift – 2-1

SECTION 2 - PROCEDURES

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

1. 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.

2. Unless specific torque requirements are given within
the text, standard torque values should be used on
heat-treated bolts, studs, and steel nuts, in accor­dance with recommended shop practices.

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

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

2. 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

Lubrication and Servicing

Components and assemblies requiring lubrication and
servicing are shown in Section 1.

2.3 LUBRICATION INFORMATION

Hydraulic System

1. 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 (suc­tion) lines.

2. 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 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.
Hydraulic system filters should be checked,
cleaned, and/or replaced as necessary, at the speci­fied intervals required in the Lubrication Chart in
Section 1 and the Preventive Maintenance and
Inspection Chart in this section. Always examine fil­ters for evidence of metal particles.

3. 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.

4. It is not advisable to mix oils of different brands or
types, except as recommended, 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 or filters of new

machines due to the wear-in of meshing compo­nents.

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.

Hydraulic Oil

1. Refer to Section1 for recommendations for viscosity
ranges.

2. JLG recommends Mobilfluid 424, which has an SAE
viscosity of 10W-30 and a viscosity index of 152.

NOTE: Start-up of hydraulic system with oil temperatures

below -26°C (-15°F). is not recommended. If it is
necessary to start the system in a sub-zero environ­ment, it will be necessary to heat the oil with a low

2-2 – JLG Lift – 3121801

SECTION 2 - PROCEDURES

density, 100VAC heater to a minimum temperature of

-26°C (-15°F).

3. The only exception to the above is to drain and fill
the system with Mobil DTE 11 oil or its equivalent.
This will allow start up at temperatures down to-29°C
(-20°F). However, use of this oil will give poor perfor­mance at temperatures above 49°C (120°F). Sys­tems using DTE 11 oil should not be operated at
temperatures above 94°C (200°F). under any condi­tion.

Changing Hydraulic Oil

1. Use of any of the recommended crankcase or
hydraulic oils eliminates the need for changing the
oil on a regular basis. However, filter elements must
be changed after the first 50 hours of operation and
every 300 hours thereafter. 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
every two years.

2. 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. Always clean the
mesh element of the filter and replace the cartridge
any time the system oil is changed.

3. 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.

2.4 CYLINDERS - THEORY OF OPERATION

Cylinders are of the double acting type. The Lift and Steer
systems incorporate double acting cylinders. A double
acting cylinder is one that requires oil flow to operate the
cylinder rod in both directions. Directing oil (by actuating
the corresponding control valve to the piston side of the
cylinder) forces the piston to travel toward the rod end of
the barrel, extending the cylinder rod (piston attached to
rod). When the oil flow is stopped, movement of the rod
will stop. By directing oil to the rod side of the cylinder, the
piston will be forced in the opposite direction and the cyl­inder rod will retract.

A holding valve is used in the Lift circuit to prevent retrac­tion of the cylinder rod should a hydraulic line rupture or a
leak develop between the cylinder and its related control
valve.

2.5 VALVES - THEORY OF OPERATION

Solenoid Control Valves (Bang-Bang)

Control valves used are four-way three-position solenoid
valves of the sliding spool design. When a circuit is acti­vated and the control valve solenoid energizes, the spool
is shifted and the corresponding work port opens to per­mit oil flow to the component in the selected circuit, with
the opposite work port opening to reservoir. Once the cir­cuit is deactivated (control returned to neutral), the valve
spool returns to neutral (center) and oil flow is then
directed through the valve body and returns to reservoir. A
typical control valve consists of the valve body, sliding
spool, and two solenoid assemblies. The spool is
machine fitted in the bore of the valve body. Lands on the
spool divide the bore into various chambers, which, when
the spool is shifted, align with corresponding ports in the
valve body open to common flow. At the same time other
ports would be blocked to flow. The spool is spring­loaded to center position, therefore when the control is
released, the spool automatically returns to neutral, pro­hibiting any flow through the circuit.

Proportional Control Valves

The proportional control valves provide a power output
matching that required by the load. A small line connected
to a load sensing port feeds load pressure back to a
sequence valve. The sequence valve senses the differ­ence between the load and pump outlet pressure, and
varies the pump displacement to keep the difference con­stant. This differential pressure is applied across the
valve’s meter-in spool, with the effect that pump flow is
determined by the degree of spool opening, independent
of load pressure. Return lines are connected together,
simplifying routing of return flow and to help reduce cavi­tation. Load sensing lines connect through shuttle valves
to feed the highest load signal back to the sequence

3121801 – JLG Lift – 2-3

SECTION 2 - PROCEDURES

valve. Integral actuator port relief valves, anti-cavitation
check valves, and load check valves are standard.

Relief Valves

Main relief valves are installed at various points within the
hydraulic system to protect associated systems and com­ponents against excessive pressure. Excessive pressure
can be developed when a cylinder reaches its limit of
travel and the flow of pressurized fluid continues from the
system control. The relief valve provides an alternate path
for the continuing flow from the pump, thus preventing
rupture of the cylinder, hydraulic line or fitting. Complete
failure of the system pump is also avoided by relieving cir­cuit pressure. The relief valve is installed in the circuit
between the pump outlet (pressure line) and the cylinder
of the circuit, generally as an integral part of the system
valve bank. Relief pressures are set slightly higher than
the load requirement, with the valve diverting excess
pump delivery back to the reservoir when operating pres­sure of the component is reached.

Crossover Relief Valves

Crossover relief valves are used in circuits where the actu­ator requires an operating pressure lower than that sup­plied to the system. When the circuit is activated and the
required pressure at the actuator is developed, the cross­over relief diverts excess pump flow to the reservoir. Indi­vidual, integral reliefs are provided for each side of the
circuit.

2.6 COMPONENT FUNCTIONAL DESCRIPTION

Hydraulic Pump

The machine is equipped with two hydraulic pumps, a
function pump and a drive pump. The function pump is a
single-section gear pump that controls the lift and steer
functions and provides a maximum output of 18 lpm (4.75
gpm). The drive pump is a single-section piston pump that
controls the drive function and provides an output of 83.3
lpm (22 gpm).

Lift Cylinder Counterbalance/Manual Descent Valve

The lift cylinder counterbalance/manual descent valve is
located on top of the lift cylinder. The counterbalance
valve is used to hold the platform in place when raised. A
cable is connected to the valve which, when pulled, manu­ally opens the lift down port and allows the platform to be
lowered in the event hydraulic power is lost.

The lift cylinder counterbalance/manual descent valve is
located on top of the lift cylinder. The counterbalance
valve is used to hold the platform in place when raised. A
cable is connected to the valve which, when pulled, manu-

ally opens the lift down port and allows the platform to be
lowered in the event hydraulic power is lost.

2.7 WEAR PADS

Sliding Pads

The original thickness of the sliding pads is 51 mm (2 in).
Replace sliding pads when worn to 48 mm (1.875 in).

2.8 CYLINDER CHECKING PROCEDURES

NOTE: Cylinder checks must be performed any time a cylin-

der component is replaced or when improper system
operation is suspected.

Cylinder w/o Counterbalance Valves - Steer Cylinder

OPERATE FUNCTIONS FROM GROUND CONTROL STATION
ONLY.

DO NOT FULLY EXTEND CYLINDER TO END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES­SURE.

1. Using all applicable safety precautions, activate
motor and fully extend cylinder to be checked. Shut
down motor.

2. Carefully disconnect hydraulic hose from retract port
of cylinder. There will be initial weeping of hydraulic
fluid which can be caught in a suitable container.
After the initial discharge, there should be no further
leakage from the retract port.

3. Activate motor and activate cylinder extend function.
Check retract port for leakage.

4. If cylinder leakage is 6-8 drops per minute or more,
piston seals are defective and must be replaced. If
cylinder retract port leakage is less than 6-8 drops
per minute, carefully reconnect hose to retract port
and retract cylinder.

5. With cylinder fully retracted, shut down motor and
carefully disconnect hydraulic hose from cylinder
extend port.

6. Activate motor and activate cylinder retract function.
Check extend port for leakage.

7. If cylinder leakage is 6-8 drops per minute or more,
piston seals are defective and must be replaced. If
extend port leakage is less than 6-8 drops per min­ute, carefully reconnect hose to extend port, then
activate cylinder through one complete cycle and
check for leaks.

2-4 – JLG Lift – 3121801

SECTION 2 - PROCEDURES

Cylinders w/Single Counterbalance Valves ­Lift Cylinder

OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION
ONLY.

1. Using all applicable safety precautions, activate
hydraulic system.

WHEN WORKING ON THE LIFT CYLINDER, RAISE THE PLAT­FORM COMPLETELY AND SUPPORT THE PLATFORM USING A
SUITABLE OVERHEAD LIFTING DEVICE.

DO NOT FULLY EXTEND LIFT CYLINDER TO END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES­SURE.

2. Raise platform completely then retract cylinder
slightly to avoid trapping pressure. Place a suitable
overhead lifting device approximately 2.5 cm (1 in)
below the platform.

3. Shut down hydraulic system and allow machine to
sit for 10-15 minutes. Carefully remove hydraulic
hoses from cylinder port block.

4. There will be initial weeping of hydraulic fluid, which
can be caught in a suitable container. After the initial
discharge, there should not be any further leakage
from the ports. If leakage continues at a rate of 6-8
drops per minute or more, the counterbalance valve
is defective and must be replaced.

5. If no repairs are necessary or when repairs have
been made, carefully reconnect hydraulic hoses to
the appropriate ports.

6. Remove lifting device from platform, activate hydrau­lic system and run cylinder through one complete
cycle to check for leaks.

2.9 LIFT CYLINDER REMOVAL AND INSTALLATION

Removal

1. Place the machine on a flat and level surface. Start
the motor and raise the platform. Shut down the
engine and attach a suitable lifting device to the plat­form.

2. Remove the bolt and locknut securing the cylinder
rod attach pin to the upper inner arm assembly.
Using a suitable brass drift, drive out the rod end
attach pin from the arm assembly.

3. Retract the lift cylinder rod completely.

4. Tag and disconnect the hydraulic lines, then cap the
lift cylinder hydraulic lines and ports.

5. Remove the bolt and locknut securing the barrel end
attach pin to the lower arm assembly. Using a suit­able brass drift, drive out the barrel end attach pin
from the arm assembly.

6. Carefully remove the cylinder from the scissor lift
and place in a suitable work area.

Installation

1. Install lift cylinder in place using suitable slings,
aligning barrel end attach pin mounting holes on
lower arm assembly.

2. Using a suitable drift, drive the barrel end attach pin
through the mounting holes in the lift cylinder and
the lower arm assembly. Secure in place with the
bolt and locknut.

3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.

4. Extend the cylinder rod until the attach pin hole
aligns with those in the upper arm assembly. Using a
suitable drift, drive the cylinder rod attach pin
through the aligned holes, taking care to align the
pin retaining hole with the hole in arm assembly.
Secure the pin in place with the bolt and locknut.

5. Lower platform to stowed position and shut down
motor. Check hydraulic fluid level and adjust accord­ingly

3121801 – JLG Lift – 2-5

SECTION 2 - PROCEDURES

Figure 2-1. Arms and Platform Positioning and Support, Cylinder Repair

.

2-6 – JLG Lift – 3121801

SECTION 2 - PROCEDURES

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

20

1. Barrel

2. Rod

3. Solenoid Valve

4. Cotter Pin

5. Cable Adaptor

6. Restrictor/Check Valve

7. Locknut

8. Wear Ring

9. Seal

10. Piston

11. O-Ring

12. Spacer

13. O-Ring

14. Back-Up Ring

15. Wear Ring

16. Seal

17. O-Ring

18. Head

19. Wiper

20. Bushing

Figure 2-2. Lift Cylinder

3121801 – JLG Lift – 2-7

SECTION 2 - PROCEDURES

Figure 2-3. Cylinder Barrel Support

Figure 2-4. Capscrew Removal

Figure 2-5. Cylinder Rod Support

2.10 CYLINDER REPAIR

Disassembly

DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON
A CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.

1. Connect a suitable auxiliary hydraulic power source
to the cylinder port block fitting.

DO NOT FULLY EXTEND CYLINDER TO END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES­SURE.

2. Operate the hydraulic power source and extend the
cylinder. Shut down and disconnect the power
source. Adequately support the cylinder rod, if nec­essary.

3. If applicable, remove the cartridge-type holding
valve and fittings from the cylinder port block. Dis­card o-rings.

4. Place the cylinder barrel into a suitable holding fix­ture..

.

6. Using a spanner wrench, loosen the end cap or
head retainer, and remove from cylinder barrel.

7. Attach a suitable pulling device to the cylinder rod
port block end or cylinder rod end, as applicable.

EXTREME CARE SHOULD BE TAKEN WHEN REMOVING THE CYL­INDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD OFF­CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON AND
CYLINDER BARREL SURFACES.

5. Mark cylinder head and barrel with a center punch
for easy realignment. Using an allen wrench, loosen
the cylinder head retainer cap screws, and remove
cap screws from cylinder barrel.

8. With the barrel clamped securely, apply pressure to
the rod pulling device and carefully withdraw the
complete rod assembly from the cylinder barrel.

9. Using suitable protection, clamp the cylinder rod in
a vise or similar holding fixture as close to the piston
as possible.

10. Loosen and remove the cap screw(s), if applicable,
which attach the tapered bushing to the piston.

2-8 – JLG Lift – 3121801