JLG 26MRT Service Manual

SERVICE & MAINTENANCE

Model

26MRT

3120892

April 11, 2000

AUSTRALIAN OFFICE

JLG INDUSTRIES, INC.

P.O. Box 5119 11 Bolwarra Road Port Macquarie, Australia Telephone: 065 811111 Fax: 065 810122

EUROPEAN OFFICE

JLG INDUSTRIES (EUROPE)

Kilmartin Place, Tannochside Park Uddingston, Scotland, G71 5PH Telephone: 01698 811005 Main Fax: 01698 811055 Parts Fax: 01698 811455

CORPORATE OFFICE

JLG INDUSTRIES, INC.

1 JLG Drive McConnellsburg, PA. 17233-9533 USA Telephone: (717) 485-5161 Fax: (717) 485-6417

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

SECTION A. INTRODUCT ION - MAINT ENA NCE SA FETY

PRECAUTIONS

A.A GENERAL

This section co nta ins the ge ne ra l s afet y pre cau tion s which must b e ob serve d d uring mai ntena nce o f the aerial platform. It i s of ut most i mport ance t hat m aintenance personnel pay strict attention to these warnings and precautions to avoid possible injury to themselves or others, or damage to the equipment. A maintenance prog ra m mus t be follo we d to e nsu re 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 du ring maintenance are inserted at the appropriate point in the manual. The se precaution s are, for the m ost 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 mechanic al 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 syst em pressu re pri or to disc onnecting 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 T HIS SECTIO N MAY RESULT IN MACHINE DAMAGE, PERSONNEL INJURY OR DEATH AND IS A SAFETY VIOLATION.

• NO SMOKING IS MANDATORY. NEVER REFUEL DURING ELECTRICAL STORMS. ENSU RE TH AT 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.

3120892 – JLG Sizzor – a

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

REVISON LOG

Original Issue - Apri l 11, 2000 (This manual split from manual 3120844)

b – JLG Sizzor – 3120892

TABLE OF CONTENTS

TABLE OF CONTENTS SUBJECT - SECTION, PARAGRAPH PAGE NO. SECTION A - INTRODUCTION - MAINTENANCE SAFE TY PRECAUTIONS

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

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

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

SECTION 1 - SPECIFI C ATIONS

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

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

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

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

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

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

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

1.8 Serial Number Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.9 Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.10 Major Component Weights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.11 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

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 Lift Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.11 Steer Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2.12 Tilt Alarm Switch Adjustment (If Equipped) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.13 Limit Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2.14 Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2.15 Drive Axle Repair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-14

2.16 Brake Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2.17 Throttle Checks and Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-26

2.18 Control Card Setup and Test Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-26

2.19 Valve Driver Card Setup Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-29

2.20 Preventive Maintenance and Inspection Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-31

SECTION 3 - TROU BL ESHOOTING

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

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

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

3120892 – JLG Sizzor – i

TABLE OF CONTENTS

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

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

1-2. Serial Number Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

1-3. Torque Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

2-1. Barrel Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-2. Cap Screw Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-3. Rod Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-4. Tapered Bushing Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2-5. Rod Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-6. Poly-Pak Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-7. Wiper Seal Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-8. Head Seal Kit Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-9. Piston Seal Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-10. Tapered Bushing Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-11. Rod Assembly Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-12. Ste e r Cyl inder Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 -10

2-13. Tilt Switch Leveling - Manual Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-14. Tilt Switch Leveling - Voltmeter Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2-15. Valve Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-14

2-16. Drive Axle Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

2-17. Carrier Section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-21

2-18. Ri ng G ear and Pinion Tooth Contact Patte rn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-22

2-19. Ring Gear Pattern Interpretation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-23

2-20. Brake Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-25

2-21. ADDCO Adjustments (Gasoline/Dual Fuel Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-27

2-22. ADDCO Adjustments (Diesel Engine). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-28

2-23. Valve Driver Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-29

3-1. Electrical Schematic - Yanmar (Sheet of 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3-2. Electrical Schematic - Yanmar (Sheet of 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-11

3-3. Electrical Schematic - Da ihatsu (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

3-4. Electrical Schematic - Da ihatsu (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

3-5. Hydraulic Schematic (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-14

3-6. Hydraulic Schematic (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

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

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

1-3 Cylinder Specificat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-4 Major Component Weights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-5 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-6 Lubrication Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

2-1 Cylinder Component To r que Specificat ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-2 Holding Valve Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-3 Preventive Maintenanc e and Safety Inspect ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32

3-1 Elevation System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2

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

3-3 Hydraulic System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

3-4 Electrical System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

ii – JLG Sizzor – 3120892

SECTION 1 - SPECIFICATIONS

SECTION 1. SPECIFICATIONS

1.1 CAPACITIES Hydraulic Oil Tank

56.8 liters (15.0 gallons)

Hydraulic System (Including Tank)

Approximately 68.1 liters (18.0 gallons)

Fue l Tank

29.5 liters (7.8 gallons)

Drive Axle

6.4 liters (3 pints)

1.2 COMPONENT DATA Engine

Daihatsu Gasoline/LP

3 cylinder, liquid-cooled 21 horsepower @ 3,000 rpm Idle - 1,500 rpm Mid Engine - 2,000 rpm High Engine - 3,000 rpm Alternator - 14 Amp Cooling System Capacit y

Drive Pump

Closed loop piston type Output - 56.8 lpm (15 gpm) @ 3,000 rpm Displacement - 19.0 cm3/rev. (1.16 in.3/rev.)

Lift/Steer Pump

Gear type Output - 11.7 lpm (3.1 gpm) @ 3,000 rpm. Displacement - 4.0 cm3/rev. (0.24 in.3/rev.).

Steer/Drive System

Steer (Front) Tires - Dico Multi-Trac C/S 26 x 12.00 - 12 NHS; 6 ply; inflate to 2.8 bar (40 psi).

Toe-In - Adjust to 6.4 mm (.25 in) overall. Drive (Rear) Tires - Dico Tru-Power TL 26 x 12.00 - 12

NHS; 6 ply; inflate to 2.8 bar (40 psi). Drive Brake - Mico hydraulic multi-disc. Drive Motor - Eaton 2000 Series; 13 1 cm3/rev. (8.0 in.3/

rev.). Drive Axle - Dana Model 44 rigid semi-float, no spin axle

assembly; 5.89 ratio; oil capacity - 1.4 liters (3 pints).

Hydraulic Filter - Inline

Return - Bypass Type 10 Microns Nominal

Engine - 1.8 liters (1.9 quarts) Crankcase Capacity - 3.0 liters (3.2 quarts)

Yanmar Diesel

3 cylinder, liquid-cooled 22 horsepower @ 3,000 rpm Idle - 1,200 rpm Mid Engine - 2,000 rpm High Engine - 3,000 rpm Alternator - 40 Amp Cooling System Capacit y

0.9 liters (1.0 quarts) - engine Crankcase Capacity - 2.4 liters (2.5 quarts)

Platform Size

Standard - 1.4 m x 2.2 m (54 in. x 88 in.)

1.3 PERFORMANCE DATA Travel Speed

Maximum Speed - 7.2 kmh (4.5 mph) Elevated Speed - 1.1 kmh (0.7 mph)

Gradeability

35%

Turning Radius

Inside - 2.5 m (8 f t . 1 in.) Outside - 4.7 m (15 ft. 4 in.)

3120892 – JLG Sizzor – 1-1

SECTION 1 - SPECIFICATIONS

Lift

Up - 34-42 seconds Down - 31-39 seconds

Platform Capacity

Standard - 455 kg (1,000 lb.)

Manual Platform Extension Capacity

115 kg (250 lb.)

Machine Weight

Approximately 2359 kg (5,200 lb.)

Wheelbase

2.0 m (78.0 in.)

Machine Height (Platform Fully Elevated)

7.9 m (26 ft.)

Machine Height (Platform Lowered)

2.3 m (89.0 in.)

Platform Railing Height

1.0 m (39.5 in.)

1.5 LUBRICATION Hydraulic Oil

Table 1-1. Hydraulic Oil

HYDRAULIC SYSTEM OPERATING

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 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.

Aside from JLG recom men da tion s , it is not advisabl e to mix oils of different brands or types, as they may not contain the same required additives or be of comparable visc osities. 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

Machine Length

2.7 m (105.0 in.)

Machine Width

1.8 m (69.0 in.)

Ground Clearance

14.0 cm (5.5 in.)

Maximum Tire Load

921 kg (2,030 lb.) @ 1.3 bar (19 psi)

1.4 TORQUE REQUIREMENTS

All wheel lug nuts should be torqued to 122 Nm (90 ft lb) every 150 hours.

NOTE: When maintenance becomes necessary or a fas-

tener has l oosen ed, re fer to the To rque Char t i n this section to determine proper torque value.

1-2 – JLG Sizzor – 3120892

SECTION 1 - SPECIFICATIONS

Lubrication Specifications

1.6 CYLINDER SPECIFICATIONS

Table 1-2. Lubrication Specifications

KEY SPECIFICATIONS

MPG Multipurpose Grease having a minimum dripping

point of 350 degress 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 Engin e (crankcase) Oil. Gas - A PI SF/SG class, MIL-

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

MIL-L-2104C.

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

Mobil 424.

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

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

1.8 SERIAL NUMBER LOCATIONS

For machine identification, a serial number plate is affixed to the machine. The plate is l ocated o n the re ar 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.

1.9 LIMIT SWITCHES

The machine is equipped with the following limit switches:

Tilt Alarm (Optional) - 5° - Illuminates a light on the platform and sounds an alarm when the machine is 5° out of level in any direction.

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

1.10 MAJOR COMPONENT WEIGHTS

Table 1-4. Major Component Weights

Table 1-3. Cylinder Specifications

Description Bore Stroke Rod Dia.

Lift Cylinder 4.00

(10.2)

Steer Cylinder (DoubleRrod)

2.00 (5.1)

39.75

(101.0)

2.69

(6.83)

1.7 PRESSURE SETTINGS

Main Relief - 145 bar (2100 psi) Steer Relief - 103 bar (1500 psi) Lift Up Relief - 145 bar (2100 psi) Lift Down Relief - 62 bar (900 psi)

2.50 (6.4)

1.25

(3.18)

Component lb kg

Platform 382 173 Manual Platform Extension 221 100 Arm Assembly (Includes Lift Cylinder) 1618 734 Chassis - w/Standard Tires 2979 1351

1.11 CRITICAL STABILITY WEIGHTS

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

Table 1-5. Critical Stability Weights

Component lb kg

Tire and Wheel Assembly - Std (each) 50 23 Daihatsu Gasoline/LP Engine 132 60 Yanmar Diesel Engine 183 81 Dana Drive Axle 130 59

3120892 – JLG Sizzor – 1-3

SECTION 1 - SPECIFICATIONS

Figure 1-1. Lubrication Diagram

Table 1-6. Lubrication Chart

INDEX

1 Wheel Bearings 2- Front Wheels MPG - repack 1200 2 Hydraulic Oil Fill Cap/Drain Plug HO - Check HO Level

3 Hydraulic Return Filter N/A N/A 50/300 4 Charge Pump Filter N/A N/A 50/300 5 Crankcase - Vanguard Gasoline/LP

6 Crankcase - Yanmar Diesel Engine FillCap/Drain Plug EO - Check EO Level

7 Rear Axle FillCap/Drain Plug EPGL - Check EPGL Level

KEY TO LUBRICANTS:

EO - Engine Oil EPGL - Extreme Pressure Gear Lubricant HO - Hydraulic Oil - Mobilfluid 424 MPG - Multi-purpose Grease

COMPONENT NUMBER/TYPE LUBE POINTS LUBE METHODS

HO - Change HO

FillCap/Drain Plug EO - Check EO Level

Engine

EO - Change EO

EPGL - Change EPGL

NOTE: 1. B e sure to lu bricate like items on each side.

2. Recommended lubricating intervals are based on maching 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 sh oul d b e vis ible i n AD D s ight wi ndow o n

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

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.

INTERVAL

HOURS

Daily/1200

Daily/50/30 0

150/1200

1-4 – JLG Sizzor – 3120892

SECTION 1 - SPECIFICATIONS

Figure 1-2. Serial Number Locati ons

3120892 – JLG Sizzor – 1-5

SECTION 1 - SPECIFICATIONS

Figure 1-3. Torque Chart

1-6 – JLG Sizzor – 3120892

SECTION 2. PROCEDURES

SECTION 2 - PROCEDURES

2.1 GENERAL

This section provides information necessary to per form maintenance on the scissor lif t. Description s, techni ques and specific procedures are designed to provide the safest and most ef fici ent main tenance for use b y person nel responsible for ensuring the correct installation and operation of machine components an d 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 GUIDAN CE 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 inf ormation is prov ided to a ssist you in t he use and application of servicing and maintenance procedures contained in this chapter.

Safety and Workmanship

Your s afety, and that of others, is the first conside ration when engaging in the maintenance of equipment. Always be conscious of weight. Never atte mpt 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 ad equate support is provided.

and fittings themselves. As soon as a line or component 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 perpend icular as possibl e to top of par t being lifted.

5. Should it be necessary to remove a c omponent on an angle, keep in mind that the capacity of an eyebolt or similar bracket lessens, as th e an gle between the supporting structure and the component

becomes less than 90°.

6. If a part resists removal, check to see whether all nuts, bolts, ca bles, br acke ts, wir ing, et c., have been removed and that no adjacent parts are interfering.

Component Disassembly and Reassembly

When disassembling or r e assembling a comp on ent, complete the procedural steps in sequence. Do not part ially 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, ot her than those recommended, without obtaining proper approval.

Pressure-Fit Parts

When assembling pressure-fit parts, use an “anti-seize” or molybdenum disulfid e base co mpound to l ubricate 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

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.

3120892 – 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 in sta lled on a sh aft, apply pres su re 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 eq uivalent material and thickness. Be sure to cut holes in the right location, as blank gaskets can cause serious system damage.

Bolt Usage and Torque Applica tion

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 hyd rau lic lines and electrical wiring, as well as their receptacles, when disco nnec ting 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 and Servicing

Components and assemblies requiring lubricat ion 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 inad equate h ydra ulic oil, a llowin g moisture, grease, filings, sealing c om po nents, sand, etc., to enter when performing maintenance, or by permitting the pump to cavitate due to insufficient system warm-up or leaks in the p ump 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 gr owth, 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 viscositie s. Good grade mineral oils, w ith viscosities suited to the ambient temperatures in which the machine is operating, are recommended for use.

Lubrication

Service applicable components with the amount, type, and grade of lubricant recommended in this manu al, 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.

NOTE: Met al p articl e s m ay appea r in th e oi l or f i lt er s o f n ew

machines due to the wear-in of meshing components.

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.

2-2 – JLG Sizzor – 3120892

SECTION 2 - PROCEDURES

NOTE: Start-up of hydraulic system with oil temperatures

below -26° C (-15° F). is not recommended. If it is necessar y to sta r t the sy ste m in a sub- zero envi ron ment, it will be necessary to heat the oil with a low 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 dow n, 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, howe ver, multi-purpose greases usually have the qualities which meet a variety of single purpose gre ase 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 t o travel t oward 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 c ylinder and it s relate d control valve.

2.5 VALVES - THEORY OF OPERATION

Solenoid Control Valves (Bang-Bang)

Control valves us ed are four-way thre e-positi on solen oid valves of the sliding spool de sign. When a cir cuit is activated and the control valve solenoid energizes, the spool is shifted and the corresponding work port opens to permit oil fl ow t o the co mpone nt in th e s elec ted circ uit, wi th 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 t o 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 contr ol valves provide a po wer output matching that required by th e load. A sma ll line connec ted 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 shuttl e valves to feed the highest load signal back to the sequence valve. Integral actuator port relief valves, anti-cavitation check valves, and load check valves are standard.

3120892 – JLG Sizzor – 2-3

SECTION 2 - PROCEDURES

Relief Valves

Main relief valves are installed at various points within the hydraulic system to protect associat ed systems a nd 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 v alve is installe d in the circuit between the pump outlet (pressure line) and the cyli nder of the circuit, generally as an integral part of the system valve bank. Relief pressures are set sl ightly higher than the load requirement, with the valve dive rting 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 requir es an ope ratin g pressur e lowe r than th at supplied to the system. When the circuit is activated and the required pres sure at th e actua tor is dev elop ed, the cross over relief diverts excess pump flow to the reservoir. Individual, integral reliefs are provided for each side of the circuit.

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 repl ac ed 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.

2.6 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 an output of 11.7 lpm (3.1 gpm). The drive pump is a single-section piston pump t hat controls the drive function and provides an output of 56.8 lpm (15 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.

2. Carefully disconnect hydrau lic ho se from retrac t 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.

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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 1 inch (2.5 cm) 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 wi ll be init ial we epin g of hyd raul ic fl uid, w hich 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.

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.

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

2.10 LIFT 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.

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.

3120892 – JLG Sizzor – 2-5

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.

SECTION 2 - PROCEDURES

Figure 2-1. Barrel Support

Figure 2-2. Cap Screw Removal

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.

5. To aid in realignment, mark cylinder head and barrel with a center punch. Using an allen wrench, loosen the eight (8) cylinder head retainer cap screws and remove cap screws from cylinder barrel.

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

Figure 2-3. Rod Support

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

10. If applicable, loosen and remove the nut which attaches the piston to the rod, then remove the piston from the rod.

6. If applicable, using a suitable spanner wrench, loosen the spanner nut retainer and remove the spanner nut from the cylinder barrel.

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

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

11. If applicable, loosen and remove the cap screw(s) securing the tapere d bushing to the piston.

12. Insert the capscrew(s) in the threaded holes in the outer piece of the tapered bushing. Progressively tighten the cap screw(s) until the b ushing is loose on the piston, then remove the bushing from the piston.

Figure 2-4. Tapered Bushing Removal

13. Screw the piston counter-clockwise, by hand, and remove the piston from the cylinder rod.

14. Remove and discard the piston o-rings, back-up rings, guidelock rings and hydrolock seals.

2-6 – JLG Sizzor – 3120892

SECTION 2 - PROCEDURES

15. If applicable, remove th e pis t on spacer from the rod.

16. Remove the rod from the holding fixture. Remove the cylinder head and retainer plate from the rod.

Cleaning and Inspection

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

2. Inspect the cylinder rod for scoring, tap e rin g, ova lity, or other damage. If necessary, dress rod with Scotch Brite or equivalent. Replace rod if necessary.

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

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

7. Inspect threaded portion of piston for damage. dress threads as necessary.

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

NOTE: Install the cylinder pin into the Gar-Max bearing dry.

Lubrication is not required with chrome pins and bearings.

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 app licable, i nspect port block fitt ings and hol ding 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.

Assembly

NOTE: Prior to cylinder assembly, ensure that the proper

cylinder seal kit is used. Apply a light film of hydraulic oil to all components

prior to assembly.

1. Using a special tool, pictured in the fo llowin g illustration, install a new rod seal into the applicable cylinder head gland groove. Refer to the following illustration for the proper tool size.

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

10. Inspect threaded portion of head for damage. Dress threads as necessary.

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

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

13. If applicable, inspect rod and barrel bearings for signs of correct lubrication and excessive wear. If necessary, replace bearings as follows:

a. Thoroughly clean steel bushing hole of burrs,

dirt, etc. to facilitate bearing installation.

b. Inspect steel bushing f or w ear or o ther da mage.

If steel bushing is worn or damaged, rod or barrel (as applicable) must be replaced.

c. Lubricate inside of steel bushing with WD-40

prior to bearing installation.

d. Using arbor of the correct size, carefully press

the bearing into the steel bushing.

Figure 2-5. Rod Seal Installation

WHEN INSTALLING NEW “POLY-PAK” TYPE PISTON SEALS, ENSURE SEALS ARE INSTALLED PROPERLY. REFER TO FIGURE 2-9., PISTON SEAL KIT FOR CORRECT SEAL ORIENTATION. IMPROPER SEAL INSTALLATION COULD RESULT IN CYLINDER LEAKAGE AND IMPROPER CYLINDER OPERATION.

3120892 – JLG Sizzor – 2-7

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