JLG 500RTS Service Manual

Service & Maintenance Manual

Model

500RTS

3121103

November 14, 2007

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

SECTION A. INTRODUCTION - MAINTENANCE SAFETY

PRECAUTIONS

A.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 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.

A.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.

A.C MAINTENANCE

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.

3121103 – JLG Sizzor – a

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

REVISION LOG

Original Issue - January 12, 2000

Revised - February 29, 2000

Revised - July 3, 2003

Revised - September 16, 2004

Revised - November 14, 2007

b – JLG Sizzor – 3121103

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

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

1.3 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

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

1.5 Lubrication Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.6 Pressure Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.7 Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.8 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.9 Serial Number Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1.10 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1.11 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

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 Sliding Wear Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

2.8 Pump Coupling Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.9 Cylinder Checking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.10 Cylinder Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.11 Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.12 Tilt Alarm Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.13 Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.14 Drive Pump Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2.15 Throttle Checks and Adjustments - Ford Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

2.16 Throttle Checks and Adjustments - Deutz F3L1011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.17 Hydraulic Component Start-Up Procedures and Recommendations . . . . . . . . . . . . . . . . . . . . . .2-12

2.18 Oscillating Axle Lockout Cylinder Bleeding Procedure - (If Equipped) . . . . . . . . . . . . . . . . . . . . .2-15

2.19 Lockout Cylinder Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

2.20 Piston Drive Motor - 2WD & 4WD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

2.21 Drive Torque Hub - 2WD/4WD Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-19

2.22 Drive Torque Hub/Brake - 4WD Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2.23 Drive Brake - 2WD/4WD Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-27

2.24 Spark Arrestor Muffler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-31

2.25 Dual Fuel/LPG System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-31

2.26 Freewheeling Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31

2.27 Limit Switch Adjustment Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

2.28 Preventive Maintenance and Inspection Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33

SECTION 3 - TROUBLESHOOTING

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

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

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

3121103 – JLG Sizzor – i

TABLE OF CONTENTS

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

1-1. Lubrication Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1-2. Serial Number Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1-3. Torque Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

2-1. Poly-Pak Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-2. Pressure Adjustment Locations (Prior to S/N 107516). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2-3. Pressure Adjustment Locations (S/N 107516 to Present) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

2-4. Throttle Checks and Adjustments - Ford VSG 413. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2-5. Precision Governor Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

2-6. Throttle Adjustments, Deutz F3L1011. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

2-7. Piston Drive Motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-18

2-8. Drive Torque Hub - (2WD/4WD rear) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2-9. Torque Hub Carrier Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2-10. Drive Torque Hub/Brake - 4WD Front. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-25

2-11. Torque Hub Cover Pipe Plug Alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28

2-12. Spring Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-28

2-13. Drive Brake - (2WD/4WD Rear) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30

2-14. Drive Hub Engaged. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

2-15. Drive Hub Disengaged . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32

2-16. Drive Cut-out Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

2-17. Drive Speed Cutout Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

3-1. Hydraulic Schematic (Sheet 1 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

3-2. Hydraulic Schematic (Sheet 2 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-3. Hydraulic Schematic (Sheet 3 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

3-4. Hydraulic Schematic (Sheet 4 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

3-5. Hydraulic Schematic (Sheet 5 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16

3-6. Hydraulic Schematic (Sheet 6 of 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

3-7. Electrical Schematic - 500 RTS Ford LRG (Sheet 1 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18

3-8. Electrical Schematic - 500 RTS Ford LRG (Sheet 2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

3-9. Electrical Schematic - 500 RTS Ford LSG (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

3-10. Electrical Schematic - 500 RTS Ford LSG (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

3-11. Electrical Schematic - 500 RTS Ford VSG (Sheet 1 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-22

3-12. Electrical Schematic - 500 RTS Ford VSG (Sheet 2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23

3-13. Electrical Schematic - 500RTS Duetz (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

3-14. Electrical Schematic - 500RTS Duetz (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25

3-15. Electrical Schematic - 500RTS Duetz (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26

3-16. Electrical Schematic - 500RTS Duetz (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27

ii – JLG Sizzor – 3121103

TABLE OF CONTENTS

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

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

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

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

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

1-5 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1-6 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

2-1 Cylinder Piston Nut Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-2 Holding Valve Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-3 Preventive Maintenance and Safety Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34

3-1 Platform Assembly - Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

3-2 Chassis Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4

3-3 Chassis Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

3-4 Hydraulic System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

3-5 Electrical System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9

3121103 – JLG Sizzor – iii

TABLE OF CONTENTS

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iv – JLG Sizzor – 3121103

SECTION 1. SPECIFICATIONS

SECTION 1 - SPECIFICATIONS

1.1 CAPACITIES

Hydraulic Oil Tank

Approximately 36.5 U.S. gallons (138.17 liters) w/10% air
space.

Hydraulic System (Including Tank)

Approximately 44 U.S. gallons (166.56 liters).

Fuel Tank

Approximately 15 U.S. gallons (56.8 liters)

Engine Crankcase

Gasoline Engine

3.4 quarts (3.2 liters) w/filter

2.9 quarts (2.7 liters) w/o filter

Diesel Engine

6.34 quarts (6.0 liters) w/filter

5.8 quarts (5.5 liters) w/o filter

Coolant Capacity (Gasoline Engine)

3.5 U.S. gallons (13.2 liters)

1.2 COMPONENT DATA

Gasoline Engine

Displacement - 4.5 liter

Manufacturer/Model - Ford LRG-425

Oil Capacity

4.5 quarts (4.3 liters) w/ filter

4.0 quarts (3.8 liters) w/o filter

Low RPM - 750

Mid RPM - 2200

High RPM - 3000

Alternator - 55 Amp external

Battery - 85 Amphour, 550 Cold Cranking Amps

Fuel Consumption

Low RPM - 1.8 gph (6.7 lph)

High RPM - 3.0 gph (11.4 lph)

Horsepower - 70 @ 2800 RPM

Coolant Capacity - 3.5 U.S. gallons (13.2 liters)

Diesel Engine

Manufacturer/Model - Deutz F3L-1011

Oil Capacity

6.34 quarts (6.0 liters) w/filter

5.8 quarts (5.5 liters) w/o filter

Mid RPM - 2000

High RPM - 3000

Alternator - 60 Amphour

Battery - 60 Amphour, 1000 Cold Cranking Amps

Fuel Consumption

Low RPM - 1.9 gph (7.19 lph)

High RPM - 2.5 gph (9.46 lph)

Horsepower - 42 @ 3000 RPM

Drive/Steer System

Tires

Standard - 12 x 16.5 NHS, 8 ply, pneumatic, inflate to 45
PSI (3.1 bar)

Optional - 31 - 15.5 x 15 NHS, 8 ply, pneumatic, inflate to
35 PSI (2.4 bar)

Optional - 12 - 16.5 NHS, 6 ply, foam filled

Steer System

Toe-In - Adjust to 1/4 inch (6.4 mm) overall

Drive Motors/Hubs/Brakes

Drive Motor - 2.48 in.3 (6.3 cm3) displacement

Drive Hub (2WD Gasoline and Diesel Engine - Rear) - Hub
ratio 35:1

Drive Hub (4WD Rear) - Hub ratio 24:1

Drive Hub/Brake (4WD Front) - Hub ratio 24:1; brake ­spring applied, hydraulic release, release pressure - 160
psi (11 bar) initial, 190 psi (13 bar) full

Drive Brake (2WD/4WD Rear) - Spring applied, hydraulic
release, release pressure - 150 psi (10 bar) initial, 170 psi
(12 bar) full

NOTE: Wheel lugs should be torqued to 80 ft lb (109 Nm) at

50 hour intervals.

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

3121103 – JLG Sizzor – 1-1

SECTION 1 - SPECIFICATIONS

Hydraulic Filter - Inline

Return - Bypass Type

25 Micron Nominal

1.3 PERFORMANCE DATA

Travel Speed

2 Wheel Drive - 3.5 mph (5.6 kmh)

4 Wheel Drive - 2.8 mph (4.5 kmh)

Gradeability

2 Wheel Drive - 25% (14°)

4 Wheel Drive - 45% (24°)

Turning Radius (Outside)

2 Wheel Steer - 13 ft 2 in (4.0 meters)

4 Wheel Steer - 6 ft 6 in (2.0 meters)

Lift Speed - 500RTS

Up - 65 - 80 seconds

Down - 70 - 80 seconds

Platform Capacity - Fixed Platform

2,500 lb. (1135 kg)

Platform Capacity - Traversing Platform Extension (If Equipped)

With Deck Extended

Main Deck - 2,000 lb (905 kg)

Extension - 500 lb (230 kg)

With Deck Retracted

2,000 lb (905 kg)

Machine Weight

Approx. 15,300 lb (6,940 kg)

Machine Height (Platform Lowered)

126.3125 in (3.15 m)

Machine Length

15 ft 5 in (4.72 meters)

Machine Width

Standard Tires - 7 ft 6 in (2.3 meters)

Foam Filled Tires - 7 ft 7 in (2.3 meters)

1.4 LUBRICATION

Table 1-1. Hydraulic Oil

HYDRAULIC SYSTEM OPERAT-

ING

TEMPERATURE RANGE

0 to +23 degrees F

(-18 to -5 degrees C)

0 to +210 degrees F

(-18 to +100 degrees C)

+50 to +210 degrees F

(+10 to +100 degrees C)

NOTE: Hydraulic oils must have anti-wear qualities at least

to API Service Classification GL-3, and sufficien­themical stability for mobile hydraulic system ser­vice. JLG Industries recommends Mobil 424
hydraulic oil, which has an SAE viscosity of 10W-20
and viscosity index of 152.

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 Mobil 424 is desired, contact JLG Industries for
proper recommendations.

SAE VISCOSITY GRADE

10W

10W-20,10W-30

20W-20

1-2 – JLG Sizzor – 3121103

SECTION 1 - SPECIFICATIONS

1.5 LUBRICATION SPECIFICATIONS

Table 1-2. Lubrication Specifications

KEY SPECIFICATIONS

MPG Multipurpose Grease having a minimum dripping

point of 350 degrees F. Excellent water resistance

and adhesive qualities, and being of extreme pres-

sure type. (Timken OK 40 pounds minimum.)

EPGL Extreme Pressure Gear Lube (oil) meeting API ser-

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

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

L-2104. Diesel - API CC/CD c lass, MIL-L-2104B/

MIL-L-2104C.

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

Mobil 424.

NOTE: Refer to Figure 1-2 for specific lubrication proce-

dures.

1.6 PRESSURE SETTINGS

NOTE: All pressures are given in pounds per square inch

(psi), with the metric equivalent, bar, in parentheses.

500RTS

1.7 LIMIT SWITCHES

The machine is equipped with the following limit switches:

High Drive Speed Cut-Out

High drive speed is cut out when platform is raised above
stowed (fully lowered) position.

Lift Cut-Out (If Equipped)

Lift is cut out at 22 ft (6.8 m) when leveling jacks are in the
stowed position.

Drive Cut-Out (If Equipped)

Drive is cut out when platform is at 22 ft (6.8 m) above
stow position, or when leveling jacks are in the set posi­tion.

1.8 CYLINDER SPECIFICATIONS

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

ric equivalent, centimeters (cm), in parentheses.

Table 1-3. Cylinder Specifications

Description Bore Stroke Rod Dia

Lift Cylinder

(400RTS/500RTS)

5.0

(12.7)

78.5

(199)

3.5

(8.9

Rexroth/Hydraforce Valve

Main Relief - 2800 psi (193 bar)

Steer Relief - 1500 psi (103 bar)

Steer Relief 4-W/S (If Equipped) - 1500 psi (103 bar)

Platform Extension (If Equipped) - 1200 psi (83 bar)

Steer Cylinder 3.0

(7.6)

Lockout Cylinder
(Oscillating Axle)

Leveling Jack

Cylinder

T r a v e r s i n g P l a t f o r m C y l i n d e r 1 . 5 ( 3 . 8 ) 4 8

3.0

(7.6)

3.0

(7.6)

7.5

(19.05)

3.75
(9.5)

18.75

(47.6)

(121)

1.5

(3.8)

1.25
(3.2)

2.0

(5.0)

1.00
(2.5)

500RTS - Tilt Alarm

A horn is sounded and a warning light is illuminated when
the machine is operated on a slope that exceeds 2 ° with
the platform raised. If the machine is operated on a 2 °
slope with the platform completely lowered, only the warn­ing light is illuminated.

3121103 – JLG Sizzor – 1-3

SECTION 1 - SPECIFICATIONS

Figure 1-1. Lubrication Diagram

1-4 – JLG Sizzor – 3121103

Table 1-4. Lubrication Chart

SECTION 1 - SPECIFICATIONS

INDEX

NO

1 Oscillating Axle Pivot Point (Optional) 1 Grease Fitting MPG - Pressure Gun 100

2 Lockout Cylinders (Optional) 2 Grease Fittings (1 each cylinder) MPG - Pressure Gun 100

3 Front Steering Spindles (2-W/D) 2 Grease Fittings MPG - Pressure Gun 100

4 Front Steering Spindles (4-W/D)

5 Tow Bar Hitch (Optional) 1 Grease Fitting MPG - Pressure Gun 100

6 Wheel Bearings (2-W/D) N/A MPG - Repack 2000

7 *Wh eel Drive Hub (4-W/D) (Optional) Fill Plug EPGL (SAE 90) 500

8 Hydraulic Oil Reservoir Fill Cap/Drain Plug HO - Check HO Level (See note 4)/

9 ** Hydraulic Filter Element N/A Initial Change - 40 Hours 250

10 *Wheel Drive Hub Fill Plug EPGL (SAE 90) 500

11 Rear Steering Spindles (4-W/S)

12 500 RTS Sizzor Arm Pivot Pins 38 Grease Fittings (500RTS) MPG - Pressure Gun 100

13 Rail Slides N/A MPG - Brush 100

14 Platform Extensi on Slides (Optional) N/A MPG - Brush 100

15 Lift Cylinder 4 Grease Fittings MPG - Pressure Gu n 100

16 Engine Crankcase Fill Cap/Drain Plug Check Engine Oil Level 10/100

COMPONENT NUMBER/TYPE LUBE POINTS LUBE METHOD

2 Grease Fittings MPG - Pressure Gun 100

(Optional)

HO - Change HO

2 Grease Fittings MPG - Pressure Gun 100

(Optional)

INTERVAL

HOURS

10/500

KEY TO LUBRICANTS:

MPG - Multi-purpose Grease

EPGL - Extreme Pressure Gear Lube

HO - Hydraulic Oil (Mobil 424)

*Torque Hubs should be 1/2 full of lubricant

** JLG Industries recommends replacing the hydraulic
filter after the first 40 hours of operation and every 250
hours thereafter.

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

NOTE: 1. Be sure to lubricate like items on each side

2. 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.

3. 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.

4. Any time the pump coupling is removed, coat
splines of coupling with Texaco Code 1912
grease prior to assembly. (gasoline or diesel
engine only).

3121103 – JLG Sizzor – 1-5

SECTION 1 - SPECIFICATIONS

Figure 1-2. Serial Number Location

1.9 SERIAL NUMBER LOCATIONS

For machine identification, a serial number plate is affixed
to the machine. On gasoline or diesel powered machines,
the plate is located on the right front side of the frame rail.
In addition, should the serial number plate be damaged or
missing, the machine serial number is stamped on the top
of frame between the front wheels.

1.10 MAJOR COMPONENT WEIGHTS

Table 1-5. Major Component Weights

Component Lb Kg

Fixed Platform (180 cm x 426 cm). 1235 560

Platform Extension. 275 125

Arm Assembly - 500RTS - Includes

Lift Cylinder.

Chassis - Includes Outriggers,

and Pneumatic Tires.

8699 3946

6052 2745

1.11 CRITICAL STABILITY WEIGHTS

DO NOT REPLACE ITEMS CRITICAL TO STABILITY WITH ITEMS
OF DIFFERENT WEIGHT OR SPECIFICATION (FOR EXAMPLE:
FILLED TIRES, ENGINE) DO NOT MODIFY UNIT IN ANY WAY TO
AFFECT STABILITY.

Table 1-6. Critical Stability Weights

Component Lb Kg

Tires (Balasted Only)12X16.5 295 134

Engine (Ford) 525 238

Engine (Deutz) 600 272

Chassis - Includes Outriggers,

and Foam-Filled Tires.

6756 3065

1-6 – JLG Sizzor – 3121103

SECTION 1 - SPECIFICATIONS

Figure 1-3. Torque Chart

3121103 – JLG Sizzor – 1-7

SECTION 1 - SPECIFICATIONS

NOTES:

1-8 – JLG Sizzor – 3121103

SECTION 2. PROCEDURES

SECTION 2 - PROCEDURES

2.1 GENERAL

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

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.

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-

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 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.

3121103 – JLG Sizzor – 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

5. 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.

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

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.

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. 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, 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.

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.

NOTE: Metal particles may appear in the oil or filters of new

machines due to the wear-in of meshing compo­nents.

Hydraulic Oil

Lubrication

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.

2-2 – JLG Sizzor – 3121103

1. Refer to Section 1 for recommendations for viscosity
ranges.

2. JLG recommends Mobil 424 hydraulic oil, which has
an SAE viscosity of 10W-20 and a viscosity index of

152.

SECTION 2 - PROCEDURES

NOTE: Start-up of hydraulic system with oil temperatures

below -15 ° F (-26 ° C). 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
density, 100VAC heater to a minimum temperature of

-15 ° F (-26 ° C).

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 -20 °
F (-29 ° C). However, use of this oil will give poor per­formance at temperatures above 120° F (49° C). Sys­tems using DTE 11 oil should not be operated at
temperatures above 200° F (94° C). under any con­dition.

Changing Hydraulic Oil

4. 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 40 hours of operation and
every 250 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
annually.

5. 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.

6. 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.

2.4 CYLINDERS - THEORY OF OPERATION

1. Cylinders are of the double acting type. The Steer,
Leveling Jack, and Deck Extension 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.

NOTE: The Lift cylinder is a single acting cylinder which take

hydraulic pressure to extend and gravity to retract.

2. A holding valve is used in the Lift, and Leveling Jack
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.

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 Section 1 for an explanation of the lubricant
key designations appearing in the Lubrication Chart.

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 cir-

3121103 – JLG Sizzor – 2-3

SECTION 2 - PROCEDURES

cuit 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

Piston Hydraulic Pump

The Sundstrand piston hydraulic pump is attached to and
driven by the gasoline or diesel engine. The pump is a 2.8

3

in

(45.9 cm3) displacement piston pump that powers the

drive motors.

2.9 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, Platform Ext. Cylinder, Axle Lockout Cylinder (If Equipped)

OPERATE FUNCTIONS FROM GROUND CONTROL STATION
ONLY.

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

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 hydraulic system and activate cylinder
extend function. Check retract port for leakage.

Gear Hydraulic Pump

The John Barnes gear pump is piggy-backed to the piston
pump, and operates all machine functions except drive.

The gear pump has a displacement of 0.6 in

3

(10.5 cm3).

Manual Descent Valve (If Equipped)

The manual descent valve is located on top of the holding
valve on the lift cylinder. The holding valve is a normally
closed solenoid valve, and holds the platform in place
when raised. When activated, the valve opens to permit lift
down. The holding valve is connected to the manual
descent valve, which is connected to a cable which, when
pulled, manually opens the lift down port of the valve and
allows the platform to be lowered in the event hydraulic
power is lost.

2.7 SLIDING WEAR PADS

The original thickness of the sliding pads is 6.0 in (15.2
cm). Replace sliding pads when worn to 5.7 in (14.5 cm).

2.8 PUMP COUPLING LUBRICATION

To insure proper operation and a long service life for the
Hayes pump coupling, it is necessary to lubricate the
splines of the coupling any time the coupling is disassem­bled or replaced. Lubricate the splines with Texaco Code
1912 Pump Coupling Grease ONLY. No other lubricant is
recommended.

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 hydraulic
system 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.

Cylinders w/Single Counterbalance Valves ­Lift Cylinder, Leveling Jacks (If Equipped)

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.

2-4 – JLG Sizzor – 3121103

SECTION 2 - PROCEDURES

2. Raise platform completely and place a suitable over­head lifting device or prop approximately 1 in. (2.5
cm) below the platform.

NOTE: Step (3) applies to the leveling jacks only.

3. Fully extend leveling jacks to check.

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

5. 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, cylinder repairs must be
made. If the retract port is leaking, the piston seals
are defective and must be replaced. If the extend
port is leaking, the counterbalance valve is defective
and must be replaced.

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

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

Lift Cylinder Installation

1. Install lift cylinder in place using suitable slings or
supports, 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
bolts, flatwashers, and lockwashers.

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. Secure the pin in place
with the bolts, lockwashers, and flatwashers.

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

2.11 CYLINDER REPAIR

NOTE: The following are general procedures that apply to

all of the cylinders on this machine. Procedures that
apply to a specific cylinder will be so noted.

2.10 CYLINDER REMOVAL AND INSTALLATION

Lift Cylinder Removal

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

2. Remove the locknut, bolts, flatwashers and keeper
shaft 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, then cap the lift cylinder
hydraulic lines and ports.

5. Remove the bolts, lockwashers, and flatwashers
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 Sizzor lift and
place in a suitable work area.

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 THE 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 appli­cable.

CYLINDERS WITH DOUBLE HOLDING VALVES. BEFORE REMOV­ING HOLDING VALVES CRACK BLEEDER TO RELEASE PRES­SURE.

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

3121103 – JLG Sizzor – 2-5

SECTION 2 - PROCEDURES

4. Place the cylinder barrel into a suitable holding fix­ture. Tap around outside of cylinder head retainer
with a suitable hammer to shatter loctite.

5. Using a suitable spanner wrench, loosen the cylin­der head retainer, if applicable, and/or cylinder head
gland, and remove from cylinder barrel.

NOTE: Steer Cylinder has two head retainers at each end of

cylinder.

Platform Ext. Cylinder has a snap ring in barrel end
of cylinder. Remove snap ring before withdraw of the
rod.

6. 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.

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

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

NOTE: On the Steer Cylinder, the rod and piston are all one

unit.

9. Remove the set screw(s), if applicable, and nut
which attach the piston to the rod, and remove the
piston. Discard nylon point set screws.

Cleaning and Inspection

1. Clean all parts thoroughly in an approved cleaning
solvent.

2. Inspect the cylinder rod for scoring, tapering, ovality,
or other damage. If necessary, dress rod with
Scotch Brite or equivalent. Replace rod if necessary.

3. Inspect threaded portion of rod for excessive dam­age. Dress threads as necessary.

4. Inspect inner surface of cylinder barrel tube for scor­ing or other damage. Check inside diameter for
tapering or ovality. Replace if necessary.

5. Inspect threaded portion of barrel for damage. Dress
threads as necessary.

6. Inspect piston surface for damage and scoring and
for distortion. Dress piston surface or replace piston
as necessary.

7. Inspect seal and o-ring grooves in piston for burrs
and sharp edges. Dress applicable surfaces as nec­essary.

8. Inspect cylinder head inside diameter for scoring or
other damage and for ovality and tapering. Replace
as necessary.

9. Inspect seal and o-ring grooves in head for burrs
and sharp edges. Dress applicable surfaces as nec­essary.

10. If applicable, inspect cylinder head retainer or end
cap for surface or thread damage. Repair or replace
as necessary.

11. Inspect cylinder head outside diameter for scoring
or other damage and ovality and tapering. Replace
as necessary.

12. If applicable, inspect thread ring for scoring or other
damage. Dress threads or applicable surfaces as
necessary.

10. Remove the piston rings.

11. Remove and discard the piston o-rings, seal rings,
and backup rings.

12. Remove the set screw, if applicable, piston spacer,
and wear ring, if applicable, from the rod.

13. Remove the rod from the holding fixture. Remove
the cylinder head gland and retainer, if applicable.
Discard the o-rings, back-up rings, rod seals, and
wiper seals.

13. If applicable, inspect rod and barrel bushings for
signs of correct lubrication and excessive wear.
Replace as necessary.

14. Inspect travel limiting collar or spacer for burrs and
sharp edges. If necessary, dress inside diameter
surface with Scotch Brite or equivalent.

15. If applicable, inspect port block fittings and holding
valve. Replace as necessary.

16. Inspect the oil ports for blockage or the presence of
dirt or other foreign material. Repair as necessary.

17. If applicable, inspect piston rings for cracks or other
damage. Replace as necessary.

2-6 – JLG Sizzor – 3121103

SECTION 2 - PROCEDURES

Assembly

NOTE: Prior to cylinder assembly, ensure that the proper

cylinder seal kit is used. Refer to the Illustrated Parts
manual.

Apply a light film of hydraulic oil to all components
prior to assembly.

WHEN INSTALLING NEW POLY-PAK TYPE PISTON SEALS (AXLE
LOCKOUT CYLINDER), ENSURE SEALS ARE INSTALLED PROP­ERLY. REFER TO FIGURE 2-1 FOR CORRECT SEAL ORIENTA­TION. IMPROPER SEAL INSTALLATION COULD RESULT IN
CYLINDER LEAKAGE AND IMPROPER CYLINDER OPERATION.

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

Table 2-1. Cylinder Piston Nut Torque Specifications

Description

Lift Cylinder 400 ft lb

Lockout Cylinder N/A N/A

Level Cylinder 400 ft lb

Platform Ext. Cylinder N/A N/A

Steer Cylinder N/A N/A

Table 2-2. Holding Valve Torque Specifications

Description Torque Value

Sun - 7/8 hex M20 x 1.5 thds 30 - 35 ft lb 41 - 48 Nm

Nut Torque

Value

(542 Nm)

(542 Nm)

Setscrew

torque Value

100 in lb
(12 Nm)

100 in lb
(12 Nm)

Figure 2-1. Poly-Pak Seal Installation

1. Place a new wiper seal and rod seal into the applica­ble cylinder head gland grooves.

2. Carefully install the head gland on the rod, ensuring
that the wiper and rod seals are not damaged or dis­lodged. Push the head along the rod to the rod end,
as applicable.

3. Carefully slide the piston spacer on the rod. If appli­cable, align the oil holes in the rod and the spacer.
Secure the spacer, if applicable.

4. If applicable, correctly place a new o-ring and back­up rings in the inner piston diameter groove.

5. Carefully place the piston on the cylinder rod, ensur­ing that the o-ring and back-up rings are not dam­aged or dislodged.

Sun - 1-1/8 hex 1 - 14 UNS thds 45 - 50 ft lb 61 - 68 Nm

Sun - 1-1/4 hex M36 x 2 thds 150 - 153 ft lb 204 - 207 Nm

Racine - 1-1/8 hex 1-1/16 - 12 thds 50 - 55 ft lb 68 - 75 Nm

Racine - 1-3/8 hex 1-3/16 - 12 thds 75 - 80 ft lb 102 - 109 Nm

Racine - 1-7/8 hex 1-5/8 - 12 thds 100 - 110 ft lb 136 - 149 Nm

7. Push the piston onto the rod until it abuts the spacer
end, apply locktite # 242 and install the attaching
nut. Refer to Table 2-1, Cylinder Piston Nut Torque
Specifications.

NOTE: On the Steer Cylinder, the rod and piston are all one

unit.

8. Prior to setscrew installation spot drill rod before
installing the setscrew(s) which secure the piston
attaching nut to the diameter groove.

9. Remove the cylinder rod from the holding fixture.

10. Place new o-rings and seals in the applicable out­side diameter grooves of both the piston and the cyl­inder head.

11. Position the cylinder barrel in a suitable holding fix­ture.

3121103 – JLG Sizzor – 2-7

SECTION 2 - PROCEDURES

EXTREME CARE SHOULD BE TAKEN WHEN INSTALLING THE
CYLINDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD
OFF-CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON
AND CYLINDER BARREL SURFACES.

12. With barrel clamped securely, and while adequately
supporting the rod, insert the piston end into the
barrel cylinder. Ensure that the piston loading o-ring
and seal ring are not damaged or dislodged.

13. Continue pushing the rod into the barrel until the cyl­inder head gland can be inserted into the barrel cyl­inder.

14. If applicable, secure the cylinder head retainer using
a suitable spanner type wrench.

15. After the cylinder has been reassembled, the rod
should be pushed all the way in (fully retracted) prior
to the reinstallation of any holding valve or valves.

16. If applicable, install the cartridge-type holding valve
and fittings in the port block using new o-rings as
applicable. Refer toTable 2-2, Holding Valve Torque
Specifications.

3. Individually push down on one corner at a time;
there should be enough travel to cause the switch to
trip. If the switch does not trip in all three tests, the
flange nuts have been tightened too far. Loosen the
nuts and repeat steps (2) and (3).

2.13 PRESSURE SETTING PROCEDURES

Rexroth/Hydraforce Valve

1. Install pressure gauge at port G on Rexroth/
Hydraforce Valve.

2. Adjust both steer section crossover reliefs all the
way in.

3. Adjust main relief cartridge out several turns.

4. Activate engine and allow hydraulic system to come
up to operating temperature.

5. Bottom out steer function. Adjust main relief to 2800
psi (193 bar).

6. Bottom out front steer right and steer left functions
and adjust each steer crossover relief to 1500 psi
(103 bar).

7. Bottom out Rear Steer Right and Steer Left functions
and adjust each Steer Crossover Relief to 1500 psi
(103 bar).

2.12 TILT ALARM SWITCH

NOTE: The machine may be equipped with a tilt alarm

switch (sensor) which is factory set to activate at 2°
that will sound an alarm and illuminate a warning
light on the platform control console. Consult factory
for tilt sensor adjustment. The only field adjustment
necessary is leveling the switch on the spring loaded
studs.

PERFORM TILT ALARM SWITCH LEVELING PROCEDURE A MINI­MUM OF EVERY SIX MONTHS TO ENSURE PROPER OPERATION
AND ADJUSTMENT OF SWITCH.

Manual Adjustment

1. Park the machine on a flat, level surface and ensure
machine is level.

NOTE: Ensure switch mounting bracket is level and securely

attached.

8. Bottom out Platform Ext. Extended functions and
adjust each Ext. Crossover Relief to 1200 psi (83
bar).

9. De-energize Platform Ext. function, shut down
motor, and disconnect pressure gauge.

2. Level the base of the indicator by tightening the
three flange nuts. Tighten each nut until bubble in
the indicator is in the center of indicator.

2-8 – JLG Sizzor – 3121103