JLG 3969 Service Manual

Service and Maintenance Manual

Models

3369electric
3969electric

3120768

March 10, 2004

ANSI

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.

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, WA TCHES AND JE WELRY 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 SIZZOR UNTIL
PLATFORM 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 AL WA YS BE DISCONNECTED DUR­ING REPLACEMENT OF ELECTRICAL COMPONENTS.

A.B HYDRAULIC SYSTEM SAFETY

• KEEP ALL SUPPOR T EQUIPMENT AND ATTACHMENTS

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.

3120768 – JLG Sizzor – a

STOWED IN THEIR PROPER PLACE.

• USE ONLY AP PROVED, NONFLAMMABLE CLEANING
SOLVENTS.

INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

REVISON LOG

March 25, 1999 - Original Issue (This man­ual was part of complete manual 3120597)

Updated November 24, 1999 - page 1-2

Updated November 24, 1999 - page 2-11

Updated March 10, 2004 - page 2-11

b – JLG Sizzor – 3120768

TABLE OF CONTENTS

TABLE OF CONTENTS

SUBJECT - SECTION, PARAGRAPH PAGE NO.

SECTION A - INTRODUCTION - MAINTENANCE SAFETY PRECAUTIONS

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

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

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

SECTION 1 - SPECIFICATIONS

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

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

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

1.4 Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

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

1.6 Pressure Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

1.7 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1.8 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1.9 critical stability weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1.10 Relays/Circuit Breakers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

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

SECTION 2 - PROCEDURES

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

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

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

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

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

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

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

2.8 Motor Controller - Modes of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.9 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-4

2.10 CYlinder Checking Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2.11 Cylinder Removal and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2.12 Cylinder Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2.13 Tilt Switch Indicator Leveling Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2.14 Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2.15 Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11

2.16 Drive Torque Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2.17 Drive Brake Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-14

2.18 Free Wheeling Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

2.19 Preventive Maintenance and Inspection Schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-16

SECTION 3 - TROUBLESHOOTING

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

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

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

3120768 – JLG Sizzor – i

TABLE OF CONTENTS (Continued)

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

1-1. Lubrication Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-2. Serial Number Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

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

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

2-2. Capscrew Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

2-3. Rod Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-4. Tapered Bushing Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7

2-5. Oil-lite Bearing Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2-6. Rod Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

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

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

2-9. Piston Seal Kit Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

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

2-11. Poly-Pak Piston Seal Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-12. Rod Assembly Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9

2-13. Pressure Setting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12

2-14. Drive Torque Hub Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2-15. Drive Brake Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15

3-1. Hydraulic Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9

3-2. Platform Wiring Diagram (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10

3-2. Platform wiring Diagram (Sheet 2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-11

3-3. Ground Control Wiring Diagram (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

3-3. Ground Control Wiring Diagram (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1-1 Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

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

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

1-4 Lubrication Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1-5 Cylinder Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1-6 Major Component Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

1-7 Critical Stability Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

2-1 Flash Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5

2-2 Cylinder Piston Nut Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2-3 Holding Valve Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

2-4 Preventive Maintenance and Inspection Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-17

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

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

3-3 Hydraulic System Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6

3-4 Electrical System Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

3-5 Flash Code Troubleshooting Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

ii – JLG Sizzor – 3120768

SECTION 1 - SPECIFICATIONS

SECTION 1. SPECIFICATIONS

1.1 CAPACITIES

Hydraulic Oil Tank

11.0 gallons (41.6 liters)

Hydraulic System

Approximately 13.2 gallons (50.0 liters)

Tor q u e H u b s ( 2 )

17 ounces (0.5 liters)

1.2 COMPONENT DATA

Battery Charger

Input, 110 VAC,60 HZ

Output, 48 VDC (23 Amp)

Batteries (8)

6 Volt, 245 AmpHour

Drive System

Drive Motor - 36 VDC, 4.1 H.P. @ 1880 rpm. continuous,
rotation - reversible

Drive Brake- 24 VDC, spring-applied, electrically released

Steer System

Tires - ST205 75R15, Load Range C, 6 Ply Rating, Poly
Filled

1.3 PERFORMANCE DATA

Travel Speed

3369/3969 electric - 3.0 mph (4.8 kmh)

High Drive for/rev (sec/50 ft) - 11-13 sec

Creep Drive for/rev (sec/50 ft) - 50-60 sec

Gradeability

25%

Turning Radius (Inside)

3369 electric - 60 in (1.52 m)

3969 electric - 60 in (1.52 m)

Turni ng Rad ius (O u tsid e )

3369 electric - 149 in (3.81 m)

3969 electric - 149 in (3.81 m)

Platform Lift Speed

3369 electric - Lift Up - 75 - 80 seconds

3369 electric - Lift Down - 50 - 60 seconds

3969 electric - Lift Up - 75 - 80 seconds

3969 electric - Lift Down - 50 - 60 seconds

Platform Capacity

3369 electric - 1000 lbs (454 kg)

3969 electric - 750 lbs (340 kg)

Platform Extension Capacity

3369 electric - 500 lbs (227 kg)

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

Hydraulic Filter

Return, 25 Micron

Hydraulic Pump/Electric Motor Assembly

Motor - 48 VDC, 5.5 H.P. @ 2500 rpm

Pump - 0.098 in.[3]/rev. (1.6 cm[3]/rev.)

Pump Output - 1.09 gpm (4.13 lpm) @ 2000 psi (137.9
Bar)

3969 electric - 500 lbs (227 kg)

Machine Weight

3369 electric - 8,000 lbs (3629 kg)

3969 electric - 8,800 lbs (3992 kg)

Machine Height (w/rails folded down)

3369 electric - 73 in (1.85 m)

3969 electric - 79 in (2.01 m)

Machine Length (stowed)

3369 electric - 109 in (2.77 m)

3969 electric - 109 in (2.77 m)

3120768 – JLG Sizzor – 1-1

SECTION 1 - SPECIFICATIONS

Machine Width

3369 electric - 69 in (1.80 m)

3969 electric - 69 in. (1.80 m)

Wheelbase

3369 electric - 77 in (1.98 m)

3969 electric - 77 in (1.98 m)

Ground Clearance

3369 electric - 7 in (17.8 cm)

3969 electric - 7 in (17.8 cm)

Maximum Tire Load

3369 electric - 3060 lb (1388 kg)

3969 electric - 3145 lb (1427 kg)

Maximum Bearing Pressure

3369 electric - 56 psi (3.9 bar)

3969 electric - 58 psi (3.9 bar)

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 index of

152.
When temperatures remain consistently below 2° F
(-7 ° C), JLG recommends the use of Mobil DTE 11.

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.

Lubrication Specifications

Table 1-3. Lubrication Specifications

KEY SPECIFICATIONS

EPGL Extreme Pressure Gear Lub e (oil) meeting API service

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

HO Hydraulic Oil. API service classification Gl-3, BP Energo l

SHS46.

LL Synthetic Lithium Lub ricant, Gredag 741 Grease.

1.4 TORQUE SPECIFICATIONS

Ta b l e 1 - 1 . To r qu e S pe ci f i c a t i o n s

DESCRIPTION

Torque Hub 75 ft. lbs.

Wheel Bolts 90 ft. lbs.

NOTE: When maintenance becomes necessary or a fas-

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

TORQUE VALUE

(DRY)

102 (NM)

(122 NM)

INTERVAL HOURS

500

50

1.5 LUBRICATION

Ta b l e 1 - 2 . Hy dr au li c O i l

Hydraulic System Operating Temper-

ature Ra nge

0° F to 23° F (-18°C to -5°C) 10W

SAE Viscosit y Grade

*MPG may be substituted for these lubricants, if neces­sary, but service intervals will be reduced.

NOTE: Refer to Lubrication Chart for specific lubrication pro-

cedures.

1.6 PRESSURE SETTINGS

Lift Up Relief - 3369ES - 2500 psi (172 bar)

3969ES - 2700 psi (186 bar)

Lift Down Relief - 1000 psi (69 bar)

Steer Relief - 1200 psi (82.74 bar)

NOTE: Main Relief at Pump - 2700 psi (186.2 bar)

0° F to 210° F (-18°C to +99°C) 10W-20, 10W- 0

50° F to 210° F (+10°C to +99°C) 20W-20

Updated 11/24/99

1-2 – JLG Sizzor – 3120768

SECTION 1 - SPECIFICATIONS

Figure 1-1. Lubrication Chart

Table 1-4. Lubrication Chart

INDEX

NUMBER

1 Hydraulic Oil Fill Cap/Drain P lug HO-Kendall Hyken 05 2 8/800 Check oil every 8 hours of operation.

2 Torque Hub Fill Plug/Half Full EPGL-SAE 90 2000 Check oil level at side plug on hub.

3 Wheel Bearings N/A MPG - Repac k 800 2 years

4 Sliding P ads Wear Pads (8) MPG - Brush 50 N/A

5 (not s hown) Hydraulic Filter Element N/A Replaceab le Element 40/250 Replace fil ter element after first 40 hours of

KEY TO LUBRICANTS:

HO - Hydraulic Oil -Kendall Hyken 052

EPGL - Extreme Pressure Gear Lube

COMPONENT

NO/TYPE LUBE

POINTS

LUBE/METHOD

NOTE: Be sure to lubricate like items on each side of the

INTERVAL

HOURS

Change oil every 800 hours of operation.

operation then ever y 250 hours thereafter.

machine.
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, lubri­cating frequencies must be increased accordingly

COMMENTS

3120768 – JLG Sizzor – 1-3

SECTION 1 - SPECIFICATIONS

1.7 CYLINDER SPECIFICATIONS

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

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

Table 1-5. Cylinder Specifications

DESCRIPTION BORE STROKE ROD DIA.

Lift Cylinder 4.00

(10.16)

Steer Cylinder

(Double Rod)

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

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

2.00

(5.08)

14.68

(37.29)

3.00

(7.62)

each direction

2.50

(6.35)

1.25

(3.18)

each rod

1.8 MAJOR COMPONENT WEIGHTS

Table 1-6. Major Component Weights

COMPONENT 3369 ELECTRIC 3969 ELECTRIC

LBS. KG. LBS. KG.

Platform 761 345 761 345

Platform Extension 320 145 320 145

Arm Assembly (Inc ludes Lift

Cylinders)

Chassis (Includes Batt ery
Box and Foam filled Tires)

Machine Complete (G VW) 8000 3629 8800 3992

3393 1539 3903 1770

3662 1661 3662 1661

1.9 CRITICAL STABILITY WEIGHTS

Table 1-7. Critical Stability Weights

COMPONENT 3369/3969 ELECTRIC

LBS. KG.

Platform 761 345

Platform Extension 320 145

Foam Filled Tires 150 68

Battery (Each) 77 35

1.10 RELAYS/CIRCUIT BREAKERS

Console Box

Relay - Potter & Brumfield P/N K10P-11D15-48 48VDC.

Circuit Breaker - Wood Electric Corp. P/N W58 x BIA4 A-5.

1.11 SERIAL NUMBER LOCATIONS

For machine identification, a serial number plate is affixed
to the front of the frame. If the serial number plate is dam­aged or missing, the machine serial number is stamped
on the right front of the machine frame.

1-4 – JLG Sizzor – 3120768

SECTION 1 - SPECIFICATIONS

Figure 1-2. Serial Number Location

3120768 – JLG Sizzor – 1-5

SECTION 1 - SPECIFICATIONS

Figure 1-3. Torque Chart

1-6 – JLG Sizzor – 3120768

SECTION 2. PROCEDURES

SECTION 2 - PROCEDURES

2.1 GENERAL

1. 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.

2. 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.

2. At any time when hydraulic oil lines are discon­nected, clear adjacent areas as well as the openings
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.

Component Removal and Installation

1. 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.

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

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

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.

3120768 – JLG Sizzor – 2-1

SECTION 2 - PROCEDURES

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 be installed.

4. Lubricate new or used serviceable bearings before
installation. When pressing a bearing into a retainer
or bore, apply pressure to the outer race. If the bear­ing is to be installed on a shaft, apply pressure to the
inner race.

Gaskets

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

Bolt Usage and Torque Application

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

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

Hydraulic Lines and Electrical Wiring

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.; 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.

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 at the specified intervals
required in Section 1. Always examine filters for evi­dence of metal particles.

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

Hydraulic System

1. Keep the system clean. If evidence of metal or rub­ber particles are 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.

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.

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 interval. When recommended lubricants are
not available, consult your local supplier for an equivalent
that meets or exceeds the specifications listed.

2-2 – JLG Sizzor– 3120768

1. Refer to Lubrication Specification Table for recom­mendations for viscosity ranges.

2. JLG recommends Kendall Hyken 052 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 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.

3. The only exception to the above is to drain and fill
the system with Mobil DTE13 oil or its equivalent.
This will allow start up at temperatures down to -20°
F. However, use of this oil will give poor performance
at temperatures above 120° F. Systems using DTE13
oil should not be operated at temperatures above
200° F under any condition.

Changing Hydraulic Oil

1. Use of any of the recommended 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.

2. Use every precaution to keep the hydraulic oil clean.
If the oil must be poured from the original container
into another, be sure to clean all possible contami­nants from the service container. Always clean the
mesh element of the filter and replace the cartridge
any time the system oil is changed.

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

Lubrication Specifications

Specified lubricants, as recommended by the component
manufacturers, are always the best choice, however,
multi-purpose greases usually have the qualities which
meet a variety of single purpose 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.

2.4 CYLINDERS - THEORY OF OPERATION

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

2. Holding valves are used in the lift circuits to prevent
retraction of the cylinder rod should a hydraulic line
rupture or leak develop between the cylinder and its
related control valve.

2.5 VALVES - THEORY OF OPERATION

Control Valves

It consists of cartridge type valves in an anodized alumi­num manifold. The cartridge valves provide for control of
flow, volume of flow and pressure in the hydraulic system.

The directional control valves are solenoid operated, three
position, 4-way sliding spool type valves. One valve is pro­vided for each of the two functions. Energizing one of the
electrical coils on a valve will divert the supply of hydraulic
oil to provide motion of that function in one direction.
Energizing the other coil will divert the oil for motion in the
other direction. When neither coil is energized, the supply
of hydraulic oil is blocked.

Flow control valves in the lift circuits provide for control of
the rate of flow when the oil is flowing out of the cap ends
of the cylinders (the load is being lowered). An adjusting
screw on each cartridge flow control valve allows the rate
of flow (speed) to be adjusted. When oil is flowing into the
cap end of the lift cylinders, an internal check valve feature
allows unrestricted flow.

Pressure relief valves limit the pressure in the steer circuit
and the rod end of each lift cylinder. When the pressure in
one of those circuits reaches the set point of the valve, the
valve opens, allowing enough flow to return to the reser­voir so that the set pressure is not exceeded. An adjusting
screw on each cartridge relief valve allows the set pres­sure to be adjusted.

The aluminum manifold provides the passages through
which the hydraulic oil is diverted to provide the desired
movement of the actuators. No moving parts of the valves
slide against the manifold and so it is not subject to wear.

3120768 – JLG Sizzor – 2-3

SECTION 2 - PROCEDURES

2.6 COMPONENT FUNCTIONAL
DESCRIPTION

Hydraulic Pump

The single stage gear pump is attached to the electric
motor located on the right rear of frame.

Manual Descent Pump

The manual operated hand pump is located on the right
rear of frame behind ground control station.

2.7 WEAR PADS

The original thickness of the sliding wear pads is 5 in (12.7
mm). Replace sliding pads when worn to 4.7 in (11.9).

2.8 MOTOR CONTROLLER - MODES OF
OPERATION

Traction Motor Drive

Drive in either forward or reverse will start only if the fol­lowing conditions are satisfied:

1. Function switches off.

Pump Motor Drive

Pump motor drive will start only if the following conditions
are satisfied:

1. FWD and REV switch off.

2. Traction mode off (brake applied).

3. TEB operate

The function is selected in a 3-second window after the
TEB has been momentarily CLOSED.

The function is selected in a 10-second window after the
TEB has been permanently CLOSED.

Another function was operated less than 3-seconds
before.

Pump drive shall only be enabled when the direction
selector inputs are in neutral and the machine is station­ary. Once pump drive mode has been entered, then the
status of the direction selector inputs shall no longer inter­lock pump operation. If a direction switch is selected dur­ing pump drive, a procedure fault will occur when the
function switch is no longer selected, remaining until both
directions and the function switch are no longer selected.

2.9 FEATURES

2. No procedure or diagnostic faults present.

3. TEB operate

The function is selected in a 3-second window after the
TEB has been momentary closed.

The function is selected in a 10-second window after the
TEB has been permanently closed.

Another function was operated less than 3-seconds
before.

4. FWD or REV selected as appropriate.

Once in “drive” mode, activating a function switch shall
not cause drive mode to be exited, the pump/traction con­tactor drive shall not be energized it will be left at the trac­tion position. If a function switch is selected during
traction, a procedure fault will occur when neutral is
selected, remaining until a function switch and both direc­tions are no longer selected.

When neutral is selected, the controller will control
smooth stopping of the machine, using plug braking,
before the electric brake is allowed to operate.

If a function switch is activated in neutral, when the vehicle
has stopped and the brake is applied, then pump mode
will become operational.

Features in Traction Mode

Maximum Speed Control.

The controller incorporates a function to limit the maxi­mum speed of the machine to a percentage of maximum
possible speed. The function operates in such a manner
as to control vehicle speed by limiting the percentage on
of the switching device to keep the machine speed below
the maximum permitted value or, if required, to apply vari­able plug braking to restrict machine speed when travel­ing down a grade. The speed is controlled based on the
percentage of accelerator input.

Features in Pump Mode

1. Proportional Control of Pump Motor Speed - The
pump motor speed shall be controlled by varying
the percentage on of the switching element in rela­tion to a separate pump accelerator input.

2. Soft Start - The pump motor speed control incorpo­rates a “soft start” facility by applying acceleration
delay to changes in the applied percentage on of
the switching element.

2-4 – JLG Sizzor– 3120768

SECTION 2 - PROCEDURES

General Features

Diagnostics

To obtain flash code, depress enable switch and repeat
operation which caused fault. After fault occurs, maintain
function position and read flash code.

NOTE: Flash code repeats after pause.

Flash code readings must be taken from platform
control box with unit switched to platform

Table 2-1. Flash Codes

Code Description

LED On Controller Operational

LED Off I nternal fault or power not turned on

1 Flash Internal fault

2 Flashes Procedure fault

3 Flashes M otor permanently low

4 Flashes Motor pe rmanently high

5 Flashes Motor neither low nor high (O pen circuit)

6 Flashes Faulty drive hand controller

7 Flashes Low battery voltage

8 Flashes Thermal cutback, controller

3. Activate hydraulic system, and activate cylinder
extend function.

4. If cylinder retract port leakage is less than 6-8 drops
per minute, carefully reconnect hose to retract port
and retract cylinder. If leakage continues at a rate of
6-8 drops per minute or more, cylinder repairs must
be made.

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

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

7. 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. If leakage continues at a rate of
6-8 drops per minute or more, cylinder repairs must
be made.

Cylinders With Single Counterbalance Valve
(Lift Cylinder)

OPERATE ALL FUNCTIONS FROM GROUND CONTROL STATION
ONLY.

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

10 Flashes Ta chometer fault

11 Flashes Tachome ter out of calibration

NOTE: Refer to Troubleshooting Section 3 for specific flash

code troubleshooting information.

2.10 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 Without Counterbalance Valves
(Steer)

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 initial discharge, there should be no further
leakage from the retract port.

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

3. After completing the above, shut down hydraulic
system and allow machine to sit for 10-15 minutes.
This is done to relieve pressure in the hydraulic
lines. Carefully remove hydraulic hoses from appro­priate cylinder port block.

4. There will be initial weeping of hydraulic fluid, which
can be caught in a suitable container. After the initial
discharge, there should not be any further leakage
from the ports. If leakage continues at a rate of 6-8
drops per minute or more, the following cylinder
repairs must be made. If the retract port is leaking,
the piston is leaking, the piston seals are defective
and must be replaced. If the extend port is leaking,
the counterbalance is defective and must be
replaced.

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

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

3120768 – JLG Sizzor – 2-5

SECTION 2 - PROCEDURES

2.11 CYLINDER REMOVAL AND
INSTALLATION

Lift Cylinder Removal

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

2. Remove the bolt, locknut 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 cylinder rod completely.

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

5. Remove the bolt, locknut 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.

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

2.12 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.

Disassembly

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

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

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

Lift Cylinder Installation

1. Install lift cylinder in place using a suitable slings,
aligning barrel end attaching 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 bolt,
locknut and keeper shaft.

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 holes with the hole on the arm assem­bly. Secure the pin in place with bolt, locknut and
keeper shaft.

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

Figure 2-1. Barrel Support

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

Figure 2-2. Capscrew Removal

2-6 – JLG Sizzor– 3120768

9. To aid in realignment, mark cylinder head and barrel
with a center punch.

10. Using a suitable spanner wrench, loosen the span­ner nut retainer and remove the spanner nut from
the cylinder barrel.

11. 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, AND PISTON. AVOID PULLING THE ROD OFF­CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON AND
CYLINDER BARREL SURFACES.

SECTION 2 - PROCEDURES

Figure 2-4. Tapered Bushing Removal

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.

Figure 2-3. Rod Support

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

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

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

11. If applicable, loosen and remove the cap screw(s)
securing the tapered 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 bushing is loose
on the piston, then remove the bushing from the pis­ton.

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.

15. If applicable, remove the piston spacer from the rod.

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 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 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.

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.

3120768 – JLG Sizzor – 2-7

SECTION 2 - PROCEDURES

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 for wear or other damage.

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.

NOTE: Install the cylinder pin into the OIl-lite bearing dry.

Lubrication is not required with chrome pins and
bearings.

der head gland groove. Refer to the following
illustration for the proper tool size.

Figure 2-6. Rod Seal Installation

WHEN INSTALLING NEW “POLY-PAK” TYPE PISTON SEALS,
ENSURE SEALS ARE INSTALLED PROPERLY. (SEE FIGURE 2-11.)
FOR CORRECT SEAL ORIENTATION. IMPROPER SEAL INSTALLA­TION COULD RESULT IN CYLINDER LEAKAGE AND IMPROPER
CYLINDER OPERATION.

2. Using a soft mallet, tap a new wiper seal into the
applicable cylinder head gland groove. Install a new
wear ring into the applicable head gland groove.

Figure 2-5. Oil-lite Bearing Installation

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.

Assembly

NOTE: Prior to cylinder assembly, ensure that the proper

cylinder seal kit is used.

NOTE: Apply a light film of hydraulic oil to all components

prior to assembly.

1. Using a special tool, pictured in the following illustra­tion, install a new rod seal into the applicable cylin-

Figure 2-7. Wiper Seal Installation

3. Place a new o-ring and back-up seal in the applica­ble outside diameter groove of the cylinder head.

Figure 2-8. Installation of Head Seal Kit

2-8 – JLG Sizzor– 3120768

4. Install a washer ring onto the rod, then 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.

5. Carefully slide the piston spacer onto the rod.

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

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

8. Carefully thread the piston on the cylinder rod hand
tight, ensuring that the o-ring and back-up rings are
not damaged or dislodged.

9. Thread the piston onto the rod until it abuts the
spacer end and install the tapered bushing.

NOTE: When installing the tapered bushing, the piston and

mating end of the rod must be free of oil.

SECTION 2 - PROCEDURES

Figure 2-10. Tapered Bushing Installation

12. Place new guidelock and hydrolock seals in the
applicable outside diameter grooves of both the pis­ton and the cylinder head.

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

Figure 2-11. Poly-Pak Piston Seal Installation

EXTREME CARE SHOULD BE TAKEN WHEN INSTALLING THE

Figure 2-9. Piston Seal Kit Installation

WHEN REBUILDING THE LIFT CYLINDER, APPLY LOCTITE #242
TO TAPERED BUSHING BOLTS, THEN TIGHTEN BOLTS
SECURELY. REFER TO TABLE 2-2, CYLINDER PISTON NUT
TORQUE SPECIFICATIONS AND TABLE 2-3, HOLDING VALVE
TORQUE SPECIFICATIONS FOR PROPER BOLT TORQUE VAL­UES.

10. Install the bolts into the bushing using Loctite #242.
Refer to Cylinder Component Torque Specifications
Table for proper bolt torque values.

11. Remove the cylinder rod from the holding fixture.

CYLINDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD
OFF-CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON
AND CYLINDER BARREL SURFACES.

Figure 2-12. Rod Assembly Installation

3120768 – JLG Sizzor – 2-9

SECTION 2 - PROCEDURES

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

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

16. Secure the cylinder head gland using the washer
ring and socket head bolts.

17. 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.

18. If applicable, install the cartridge-type holding valve
and fittings in the port block using new o-rings as
applicable.

WHEN REBUILDING THE LIFT CYLINDERS, APPLY LOCTITE 242
TO PISTON NUT AND SETSCREWS.

Table 2-2. Cylinder Piston Nut Torque Specifications

Description Nut Torque Value

(Wet)

Lift Cylinder 400 ft. lbs.

(542 NM)

Steer Cylinder N/A N/A

Setscrew Torque

Value (Dry)

100 in. lbs.

(12 NM)

NOTE: These cylinders use setscrews which should be dis-

carded and replaced whenever they are removed.

19. Remove cylinder rod from the holding fixture.

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

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

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.

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

23. Continue pushing the rod into the barrel until the cyl­inder head gland can be inserted into the barrel cyl­inder or if applicable until the cylinder head threads
engage the barrel threads.

24. If applicable, apply loctite #222 and secure the cyl­inder head retainer using a suitable chain wrench.

NOTE: Step (16) applies to the Steer Cylinder.

25. Insert the other cylinder head gland into the barrel
cylinder. Secure the cylinder head retainer using a

Table 2-3. Holding Valve Torque Specifications

Description Torque Value

Sun - 7/8 hex M20 x1.5 thds 30-35 ft lb

(41-48 Nm)

Sun - 1-1/8 hex 1 - 14 UN S thds 45 -50 ft lb

(61-68 Nm)

Sun - 1-1/4 hex M36 x 2 thds 150-160 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)

IF THE CYLINDER IS TO BE TESTED PRIOR TO INSTALLATION ON
THE MACHINE, EXTREME CARE SHOULD BE USED TO INSURE
THAT THE OUTER END OF THE ROD IS SUPPORTED. USE
EITHER A TRAVELING OVERHEAD HOIST, FORKLIFT, OR OTHER
MEANS TO SUPPORT THE OVERHANGING WEIGHT OF THE
EXTENDING ROD.

suitable chain wrench.

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

27. If applicable, install the cartridge type holding valve
and fittings in the rod port block using new o-rings
as applicable. Refer to Table 2-3, Holding Valve
Torque Specifications for proper torque.

2-10 – JLG Sizzor– 3120768

SECTION 2 - PROCEDURES

2.13 TILT SWITCH INDICATOR LEVELING
PROCEDURE

PERFORM TILT 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. Be sure it is
as level as possible, with tires filled to rated pres­sure.

NOTE: Ensure switch mounting is level and securely

attached.

2. Tighten the three flange nuts with a socket wrench.
Each nut should be tightened approximately one­quarter of its spring’s travel.

3. Using bubble level on top of indicator, Tighten or
loosen the three flange nuts until indicator is level.

4. Individually push down on one corner at a time.
There should be enough travel to cause the indica­tor to trip. If the indicator does not trip in all three
tests, the flange nuts have been tightened too far.

2.15 PRESSURE SETTING PROCEDURES

Main Relief at Pump

1. Install pressure gauge at port “G” on 4640915 valve.

2. Activate and bottom out Lift Up. Adjust Main Relief to
2500 psi (172.37 bar).

Lift UP Relief

1. With pressure gauge at “G” port on 4640915 valve,
activate and bottom out Lift Up.

2. Adjust Lift Relief to 2500 psi (172 bar).on the 3369ES
and 2700 psi (186 bar) on the 3969ES

Lift Down Relief

1. With pressure gauge at “G” port on 4640915 valve,
activate and bottom out Lift Down.

2. Adjust Lift Relief to 900 psi (62.06 bar).

Steer Relief

1. With pressure gauge at “G” port on 4640915 valve,
activate and bottom out Steer Left or Right.

2.14 LIMIT SWITCHES

Drive Cut-Out Limit Switch (3969electric)

This switch is located on the front of the machine frame.
Adjust cam to trip limit switch when platform is elevated to
32 ft (9.75 m).

High Speed Drive Cut-Out

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

NOTE: There is no adjustment to be made to the Platform

Ext. limit switch which bolts on the bottom of the plat­form (If Equipped).

2. Adjust Steer Relief to 1200 (82.7 bar).

3. Shut down hydraulic system and remove pressure
gauge.

Updated 11/24/99

3120768 – JLG Sizzor – 2-11

SECTION 2 - PROCEDURES

Figure 2-13. Pressure Setting Procedures

2.16 DRIVE TORQUE HUB

Disassembly

1. Loosen all cover bolts (28 & 29) and drain oil from
unit.

2. Remove the cover bolts (28 & 29) and lift off input
cover. Remove and discard o-ring from counterbore
of input cover.

3. Remove sun gear and thrust washer.

4. Lift out the carrier and thrust washer.

5. Remove input spacer.

6. Lift out internal gear and thrust washer.

7. While wearing eye protection, remove the retaining
ring from the output shaft and discard.

8. Remove thrust washer from the output shaft.

9. The output shaft may now be pressed out of the
housing.

10. The bearing cups will remain in hub as will the inner
bearing cone. The outer bearing cone will remain on
the output shaft. The lip seal will be automatically
removed during this procedure.

NOTE: If bearing replacement is necessary, the bearing

cups can be removed with a slide hammer puller or
driven out with a punch.

11. To remove the cluster gears from the carrier, drive
the roll pin into the planet shaft. The planet shaft
may now be tapped out of the carrier. After planet
shaft has been removed, the roll pin can be driven
out.

2-12 – JLG Sizzor– 3120768

SECTION 2 - PROCEDURES

Figure 2-14. Drive Torque Hub Assembly

12. The cluster gear can now be removed from the car­rier). The tanged thrust washer will be removed from
the cluster gear.

13. The needle bearings and thrust spacer are now
removed from cluster gear.

NOTE: When rebuilding or repairing the unit, the retaining

ring (9), o-rings (22), and seal (2) should always be
replaced.

Assembly

1. With the hub shaft sub-assembly resting on the shaft
install internal gear. The spline of the internal gear.
bore will mesh with the spline of the output shaft.

2. Thrust washer (27) is installed on the face of the out­put shaft. Sufficient grease or petroleum jelly should
be used to hold thrust washer in place.

3120768 – JLG Sizzor – 2-13

SECTION 2 - PROCEDURES

3. Place o-ring into hub counterbore. Use petroleum
jelly to hold in place. Locate and mark the four
counter beamed holes in the face of the housing.
This is for identification later in the assembly.

4. Thrust spacer (25) is installed into the bore of the
output shaft. This should be a slip fit and the thrust
spacer should rotate in this location.

5. Place carrier assembly on a flat surface with the gear
cluster up. Find the punch marked tooth on each
large gear and locate at 12 o’clock (straight up) from
each planet pin.

6. With shoulder side of ring gear facing down, place
ring gear over (into mesh with) cluster gear. Be sure
that punch marks remain in correct location during
installation. The side of the ring gear with an “X”
stamped on it should be up.

7. While holding ring gear and cluster gear in mesh,
place small side of cluster gear into mesh with the
internal gear and sun gear. On the ring gear, locate
the hole marked “X” over one of the marked coun­terbored holes in hub.

NOTE: If gears do not mesh easily or carrier assembly does

not rotate freely, then remove the carrier and ring
gear and check the cluster gear timing.

8. Sun gear is installed, meshing with the teeth of the
large diameter cluster gear. The counterbore on the
sun gear locates on the shoulder of the input spacer.
This is to be a slip fit and should operate freely.

9. Thrust washer is installed onto the sun gear and
should locate on the gear teeth shoulder.

10. Thrust washer is installed into the counterbore of the
carrier.

11. Place o-ring into input cover counterbore. Use petro­leum jelly to hold o-ring in place.

12. The input cover is now installed on this assembly.
Taking care to correctly align pipe plug hole with
those in the hub, usually 90 degrees to one another,
locate the four counterbore holes in housing,
marked in step (3) and install four shoulder bolts. A
tap with a hammer may be necessary to align shoul­der bolt with hub counterbore.

2.17 DRIVE BRAKE ASSEMBLY

Disassembly

1. After removing brake from its installation, place
brake on a clean dry work bench with mounting
plate uppermost.

2. Unscrew the socket head bolts in equal increments
to ensure the spring pressure within the brake is
reduced gradually and evenly.

3. Remove and lay aside the shaft and mounting plate
sub-assembly. Should it be necessary to replace
ball bearings, retainer rings and press bearing off.

4. Remove friction plate and spacers and set aside.
Spacers are factory set for each brake to obtain
required air-gap and are not interchangeable
between brakes.

5. Armature and compression springs can be removed
and set aside.

Inspection

1. Inspect the friction plate and the mating surfaces on
the armature and mounting plate for wear and/or
damage.

2. Examine the compression spring.

3. Examine the friction plate and the shaft for wear and/
or damage to the spline.

4. Examine the pole faces of the magnet and the arma­ture for bruises, swellings or damage. Any bruises,
swellings or damage should be stoned flat.

5. Examine input and output splines of shaft for wear
and/or damage.

6. Check ball bearing for axial float and/or wear.

NOTE: It is essential when replacing the friction plate that

spacers are also replaced.

Assembly

1. Clean all parts thoroughly.

2. Reverse disassembly procedure above, taking par­ticular care with the assembly sequence of the fric­tion plate.

13. Install bolts into remaining holes.

14. Pipe plugs are to be installed into input cover using
a lubricant seal.

15. Torque bolts (28 & 29) to 23 - 27 ft. lbs. (31- 36 NM).

16. Fill unit one-half full with EP90 lubricant.

NOTE: Assemble friction plate with two center-punches fac-

ing towards mounting plate.

3. If a new plate has been fitted, then new spacers will
have to be adjusted for air gap of 0.014 - 0.024
inches (0.35 - 0.60 mm).

4. After checking air gap, connect power supply.

2-14 – JLG Sizzor– 3120768

SECTION 2 - PROCEDURES

Figure 2-15. Drive Brake Assembly

5. Switch on power supply and ensure brake fully
releases.

6. The brake can be adjusted for friction plate wear by
removing spacers and machining them to maintain
the correct air gap. Length of all three spacers
should be within 0.001 in. (0.025 mm)

2.18 FREE WHEELING PROCEDURE

Use the following procedures ONLY for emergency move-
ment to a suitable maintenance area.

1. Chock all wheels securely.

2. Engage the mechanical release on both brakes by
loosening, completely reversing (towards drive
motor) and tightening the three nuts on each brake.

3. Connect suitable equipment, remove chocks, and
move machine.

4. After moving machine, position on a firm, level sur­face.

5. Chock wheels securely.

6. Disengage the mechanical release on both drive
brakes by loosening, completely reversing (towards
torque hub) and tightening the three nuts on each
brake.

7. Remove chocks from wheels as desired.

3120768 – JLG Sizzor – 2-15

SECTION 2 - PROCEDURES

2.19 PREVENTIVE MAINTENANCE AND
INSPECTION SCHEDULE

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

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

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

NOTE: This machine requires periodic safety and mainte-

nance inspections by a JLG Dealer. A decal located
on the frame affords a place to record (stamp)
inspection dates. Notify dealer if inspection is over­due.

The inspection and maintenance code numbers are as fol­lows:

1. Check for proper and secure installation.

2. Check for visible damage and legibility.

3. Check for proper fluid level.

4. Check for any structural damage; cracked or broken
welds; bent or warped surfaces.

5. Check for leakage.

6. Check for presence of excessive dirt or foreign
material.

7. Check for proper operation and freedom of move­ment.

8. Check for excessive wear or damage.

9. Check for proper tightness and adjustment.

10. Drain, clean and refill.

11. Check for proper operation while engine is running.

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

12. Check for proper lubrication.

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

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

15. Check for proper inflation.

16. Clean or replace suction screen.

2-16 – JLG Sizzor– 3120768

Table 2-4. Preventive Maintenance and Inspection Schedule

AREA INTERVAL

PLATFORM

1. Controller 1, 11

2. Switches 1, 11

3. Placards and Deca ls 1, 2

4. Control Tags 1, 2

5. Hoses and Cables 1 4, 8

6. Wear Pads 8

7. Handrail and Chains 1, 4

CH A S SI S

1. Batteries 3 5

2. Battery Charger 1

3. Hydraulic Pump/Motor 1 5

4. Valves 1 5

5. Hydraulic Filter 5, 14 14

6. Hydraulic Hoses and Tubing 1 5

7. Hydraulic Oil Tank* 3 5 4

8. Breather - Hydrauli c Tank 6, 14

9. Lift Cylinder 1 5, 6,13 4

10. Limit Switch 1, 7

11. Placards and Decals 1, 2

12. Wheel and Tire Assemb lies 1 8, 9

13. Drive Motors 1, 5, 6

14. Drive Torque Hubs 1, 3, 5, 6

15. Drive Brakes 1, 6 8

16. Steer Cylinder 1 5, 6, 13 4

17. Steer Components 1 4, 6 8

18. Wheel Bearing s 8

19. Sizzor Arms 1, 4

20. Safety Prop 1, 4

21. Wear Pads 8

22. Pivot Pins/Bolts 1, 4 7, 8

23. Switches, Ground Contro l 1, 11

24. Control Tags 1,2

25. Hose and Cable 1 4, 8

* Inspection and Maintenance Code 10 to be performed annually.

10 HOURS

DAILY

50 HOURS

WEEKLY

200 HOURS

MONTHLY

SECTION 2 - PROCEDURES

500 HOURS

3 MONTHS

1000 HOURS

6 MONTHS

3120768 – JLG Sizzor – 2-17

SECTION 2 - PROCEDURES

This page intentionally left blank.

2-18 – JLG Sizzor– 3120768

SECTION 3 - TROUBLESHOOTING

SECTION 3. TROUBLESHOOTING

3.1 GENERAL

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

3.2 TROUBLESHOOTING INFORMATION

1. The troubleshooting procedures applicable to the
aerial platform are listed and defined in Tables 9-1
through 9-4. As an aid to table use, the aerial plat­form is divided into four major groups, each covered
separately within this section. These groups are as
follows: elevation system, chassis assembly,
hydraulic system and electrical system.

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

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

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

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

3.3 HYDRAULIC CIRCUIT CHECKS

The reference for improper function of a hydraulic system,
where the cause is not immediately apparent, should be
the Troubleshooting Chart. The best place to begin the
problem analysis is at the power source (pump). Once it is
determined that the pump is serviceable, then a system­atic check of the circuit components, beginning with the
control, would follow. For aid in troubleshooting, refer to
the Illustrated Parts Manual for hydraulic diagrams of the
various circuits.

3120768 – JLGSizzor – 3-1

SECTION 3 - TROUBLESHOOTING

Table 3-1. Platform Assembly Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

PLATFORM ELEVATION SYSTEM

No response to control switc h Enable switch not acti vated Activate enable s witch

Function not activated w ithin 3 seconds after
enable switch was de pressed

Enable switch not fu nctioning properly Replace enable switch c ircuit card

Lift control switch i noperative Replace control switc h

Hydraulic oil sys tem low Replenish oil system neces sary

Restricted or brok en supply line on valve or pump Clean, repair or repla ce as necessary

Control valve not fun ctioning properly Repair or repl ace valve

Lift cylinder not fu nctioning properly Repair or replac e lift cylinder

Hydraulic pump not functioning prop erly Check Sevcon control contactors for proper func-

Low battery voltage Check voltage and charge batteri es or replace

Platform will not raise Enable swi tch not activated Activat e enable switch

Function not activated w ithin 3 seconds after
enable switch was de pressed

Enable switch not fu nctioning properly Replace enable switch c ircuit card

Load capacity exceeded. (Person nel and/or
equipment on platfor m)

Reactivate enable switc h

tioning

batteries as necessa ry

Reactivate enable switc h

Reduce load to r ecommended capacity

Hydraulic oil sys tem low Replenish oil as neces sary

Restricted or brok en oil line or fitting Clean, repair or replace as necessary

Control valve not fun ctioning properly Repair or repl ace valve

Lift cylinder not fu nctioning properly Repair or replac e lift cylinder

Motor/Pump does no t respond when lift control
switch is moved to the up position

No electrical si gnal being sent to lift up control
valve cartridge

Pressure set to lo w on pump Check pressure and res et as necessary

Platform will not lower No electrical signal being sent to lift down control

valve cartridge

Lift down control cartridge not functioning prop­erly

Lift cylinder not fu nctioning properly Repair or replac e lift cylinder

Refer to the electric al schematic and/or electrical
system troublesh ooting chart

Refer to the electric al schematic and/or electrical
system troublesh ooting chart

Refer to the electric al schematic and/or electrical
system troublesh ooting chart

Repair or replace li ft down control cartridge

3-2 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Table 3-1. Platform Assembly Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

Platform raises or lowers erratically Enable switch no t activated Activate enabl e switch

Function not activated w ithin 3 seconds after
enable switch was de pressed

Enable switch not functioning properly replace enable sw itch circuit card

Hydraulic system low replenish oil a s necessary

Restricted or broken hydrau lic line or fitting Clean, repair or replace as necessary

Control valve not fun ctioning properly Repair or repl ace valve

Worn seals in lift c ylinder Replace seals

Cylinder not functioni ng properly Repair or replace cylinder

Platform drifts down Worn seals in lift c ylinder Replace seals

Manual descent valv e open Close manual descent valve

High drive does not operate below horizontal Damaged wiring on li mit switch Repair or replace wiri ng

Damaged limit sw itch Replace limit switch

Reactivate enable swi tch

3120768 – JLGSizzor – 3-3

SECTION 3 - TROUBLESHOOTING

Table 3-2. Chassis Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

DRIVE SYSTEM

No response to control Enable switch not activated Activate enable switc h

Function not activate d within 3 seconds after
enable switch was depressed

Enable switch not functioning proper ly Replace enab le switch circuit card

Drive motor(s) not functioning pro perly Repai r or replace drive motors

Damaged wiring on hand controller See wiring sch ematic.repair or replace wiri ng as

Sevcon overheated Check flashcode

Defective hand control ler Repair or replace hand controller

Damaged wiring on motor controller See wiring schematic . repair or replace wiring as

Defective enable swi tch Repair or replac e enable switch

Defective motor co ntroller Check flashcode. Repl ace motor controller

Defective motor co ntroller contactors Repair or replac e contactors

Low battery Check flashcode on sevcon

Machine will not travel forward Enable s witch not activated Activate e nable switch

Function not activate d within 3 seconds after
enable switch was depressed

Enable switch not functioning proper ly Replace enab le switch circuit card

Reactivate enable switch

necessary

necessary

Reactivate enable switch

Drive motor(s) not functioning pro perly Repai r or replace drive motors

Brake(s) not re leasing Repair or replac e electric brake

Motor/Pump will not res pond when drive control
moved to forward

Motor controller forward con tactor defective Repair or replac e contactor

Machine will not travel in rev erse Motor c ontroller reverse contactor d efective Repair or rep lace contactor

Se e mach ine will not travel forward

Machine travels very slow below horizontal Defective hand controller Che ck flashcode on Sevcon (6 flashes )

Sevon controller not programmed properly Rep rogram Sevcon

Drive system very jerky Sevcon controller defecti ve Check flashcode

Machine will speed up in forward or reverse Wires loose or broken from Tach Drive system to

Sevcon controll er

Ta ch Drive shaft broke off Replace Tach Drive shaft

Ta ch Drive defective Check flashcode

Refer to electrical system troubleshooting

Check flashcode o n Sevcon. Repair or replace wi re
as necessary

3-4 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Table 3-2. Chassis Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

STEER SYSTEM

No response to control Enable switch not activated Activate enable switc h

Function not activate d within 3 seconds after
Enable switch was d epressed

Enable switch not functioning proper ly Replace enab le switch circuit card

Hydraulic syst em low Rep lenish oil as necessary

Damaged wiring on cont rol switch or solenoid
valve

Control switch not fun ctioning properly Replace switch

Resrticted or broke n hydraulic line on steer valve
or hydraulic pump

Control valve not functioning pro perly Repair or replace contro l valve

Steer cylinder not functioni ng properly Rep air or replace steer cy linder

Machine hard to steer or steering erratic Hydraulic system oil low Replenish oil as n ecessary

Restricted hydrauli c line or fitting Clean re pair or replace hydraulic l ine or fitting

Bent steering linkage Repair or replace steeri ng linkage as required

Hydraulic pump not fu nctioning properly Repair or replace hydrau lic pump

Steer cylinder not functioni ng properly Rep air or replace steer cy linder

Steering inoperative Wiring damaged on contr ol switch or solenoid

valve

Reactivate enable switch

Repair or replace wiri ng as necessary

Clean repair or replace hydraulic line

Repair or replace wiring

Solenoid valve n ot functioning properly Repair o r replace solenoid valve

Steer control switch not f unctioning properly Replace steer contro l switch

Steer cylinder not functioni ng properly Rep air or replace steer cy linder

Machine will not steer left or right Enable switch not activated Activate enable s witch

Function not activate d within 3 seconds after
enable switch was depressed

Enable switch not functioning proper ly Replace enab le switch circuit card

Wiring on steer control switc h damaged Repair or replace wiri ng as necessary

Wiring on steer solenoid valv e damaged Repair or replace wiring as nec essary

Steer solenoid coil damaged Replace coil

Bent steer cylinder rod Repair or rep lace cylinder

Damaged steer linkage Rep air or replace steer linkage

Reactivate enable switch

3120768 – JLGSizzor – 3-5

SECTION 3 - TROUBLESHOOTING

Table 3-3. Hydraulic System Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

HYDRAULIC SYSTE M - GENERAL

Hydraulic pump noisy Air bubbl es in oil Reservoir oil l evel low. Replenish oil as neces-

sary

Oil filter dirty Replace oil filter

Pump cavitating. (Vacuum in pump due tooil
starvation)

System overheating Oil viscosity too high Drain hydraulic system and replace with recom-

Pump not delivering oil Defective motor on pump Repair or replace motor

System pressure too low Leak in component, line or fitting Repair or replace component , line or fitting

Systems operate erratically Sticking or binding valve cartridge, pis ton rod,

Oil in reserv oir low Repl enish oil as necessary

Restricted re servoir air vent Clean air v ent

Oil viscosit y too high Dra in hydraulic system and repl ace with recom-

mended oil

Leak in suction line Repair or replace s uction line

mended oil

Hydraulic oil lo w in reservoir Replenish oilt o proper level

Extended driving per iods Do not drive machine f or extended periods

Hydraulic pump not func tioning properly R epair or replace pump

Defective valve c artridge R eplace cartridge

Clean, repair or r eplace components as

etc.

Hydraulic oil not at operating temperature Allow oil sufficient time to wa rm up

required

3-6 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Table 3-4. Electrical System Troubleshooting

TROUBLE PROBABLE CAUSE REMEDY

ELECTRICAL SYSTEM

Hand controller N o electric power to hand controller Check electr ical input to hand controller

Control valve will not function when thumb­switch is moved in either direction

No response to a function control switch Eme rgency stop switch no positioned pr operly Place emergency stop switch to o n position

Drive motors will not function when hand
controller is activated

No electric power to valve Chec k electric output and electric al signal at the

valve

Improper ground Check for proper grounding

Platform/Ground sel ect switch not positioned
properly

Batteries defectiv e or require charging Check batteries for service ability. R eplace or

No voltage supplied to drive motors Check motor cont roller and contactors for

Defective function swi tch Replace switch

Defective circuit b reaker Replace circu it breaker

No voltage prese nt at applicable control valve Check applicable wi re for proper connection.

Defective motor/pump assembly Replace motor/pump ass embly

Motor controller 200 Amp fuse blo wn C heck flashcode on Sevcon and determine

Place Platform/Ground select switch to proper
position

charge batteries as necessary

proper functioning. Repair or replace as neces­sary

Using suitable test meter, perform continuity test
on wire. Repair or r eplace wire as necessary

cause and repair. Replace fuse

Hydraulic pump/motor will not run Batteries require charging or will not charg e Charge or replace batteries as r equired

Motor controller con tactors not functioning prop­erly

Pump/motor not functioni ng properly R epair or replace pump/motor

Motor controller malfunctioning See re medy column Refer to flash code troubleshooting chart

Repair or replace contac tors

3120768 – JLGSizzor – 3-7

SECTION 3 - TROUBLESHOOTING

Table 3-5. Flash Code Troubleshooting Messages

CODE MESSAGE REMEDY

1 Flash Internal fau lt Replace MOS90

2 Flashes* C heck enable wiring

Check for corr ect start up sequence
Check that both direc tions are not selected

3 Flashes Check p ower and control wiring for shorts

Replace controller

4Flashes Check dir ection contactor tips

Check power wiri ng for shorts
Check motor for arm ature to field shorts
Check for shorts to frame and battery leakage
Replace controller

5 Flashes Check c ontactor tips

Check contactor for mechanical operation and c oil
check power and control wir ing
Check motor
Replace controller

6 Flashes Check o peration of hand controller with Test Sequence

Check pot operati on with voltmeter for voltage a t minimum
setting
Replace controller

7 Flashes Check b attery voltage with voltmeter

Check power connect ions, fuses, etc.
Check for battery leakage to frame
Replace controller

Retry
Retry
Select only one di rection

Rectify

Free/change tips
Rectify
Rectify
Rectify

Repair/replace
Repair/replace
Rectify
Rectify

Rectify/replace
Adjust as necessa ry or replace

Change/charge batter y
Repair or replace
Rectify

8 Flashes Check c urrent draw

Check mounting and heat sinking of controller

10 Flashes Check tach ometer wiring

Check speed tachomete r
Replace tachometer

11 F las hes Recycle emergency stop sw itch

Check pin voltage

NOTE: If the machine is operated at a very slow speed or stalled when climbing a grade of 20% or greater, a 10 flash fault will

occur. recycle the emergency stop switch to recover.

NOTE: All flash codes must be checked with unit switched to platform control

* If speed switch is turned 25% - 50% toward full speed, Sevcon controller will give a 2 flash fault indicating a procedure
fault. If, while 2 flash fault is being indicated, the speed control knob is turned to less then 25% the 2 flash fault will stop
and LED will come on steady, indicating controller operational.

Rectify
Rectify

Repair
Rectify

Replace tachometer PC board

3-8 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Figure 3-1. Hydraulic Schematic

3120768 – JLGSizzor – 3-9

SECTION 3 - TROUBLESHOOTING

Figure 3-2. Platform Wiring Diagram (Sheet 1 of 2)

3-10 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Figure 3-2. Platform wiring Diagram (Sheet 2 of 2)

3120768 – JLGSizzor – 3-11

SECTION 3 - TROUBLESHOOTING

Figure 3-3. Ground Control Wiring Diagram (Sheet 1 of 2)

3-12 – JLG Sizzor – 3120768

SECTION 3 - TROUBLESHOOTING

Figure 3-3. Ground Control Wiring Diagram (Sheet 2 of 2)

3120768 – JLGSizzor – 3-13

SECTION 3 - TROUBLESHOOTING

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3-14 – JLG Sizzor – 3120768

McConnellsburg PA. 17233-9533

JLG Worldwide Locations

Corporate Office

JLG Industries, Inc.

1 JLG Drive

USA

Phone: [phone]

Fax: [phone]

JLG Industries (Australia)
P.O. Box 5119
11 Bolwarra Road
Por t Macqu ari e
N.S.W. 2444
Australia
Phone: [phone]
Fax: [phone]

JLG Latino Americana Ltda.
Rua Eng. Carlos Stevenson,
80-Suite 71
13092-310 Campinas-SP
Brazil
Phone: [phone]
Fax: [phone]

JLG Industries (Europe)
Kilmartin Place,
Tannochside Park
Uddingston G71 5PH
Scotland
Phone: [phone]
Fax: [phone]

JLG Industries (UK)
Unit 12, Southside
Bredbury Park Industrial Estate
Bredbury
Stockport
SK6 2sP
England
Phone: [phone]
Fax: [phone]

JLG Europe B.V.
Jupiterstraat 234
2132 HJ Foofddorp
The Netherlands
Phone: [phone]
Fax: [phone]

JLG Industries (Pty) Ltd.
Unit 1, 24 Industrial Complex
Herman Street
Meadowdale
Germiston
South Africa
Phone: [phone]
Fax: [phone]

JLG Deutschland GmbH
Max Planck Strasse 21
D-27721 Ritterhude/lhlpohl
Bei Bremen
Germany
Phone: [phone]
Fax: [phone]

JLG Industries (Norge AS)
Sofeimyrveien 12
N-1412 Sofienyr
Norway
Phone: [phone]
Fax: [phone]

Plataformas Elevadoras
JLG Iberica, S.L.
Trapadella, 2
P.I. Castellbisbal Sur
08755Castellbisbal
Spain
Phone: [phone]
Fax: [phone]

JLG Industries (Italia)
Via Po. 22
20010 Pregnana Milanese - MI
Italy
Phone: [phone]
Fax: [phone]

JLG Polska
UI. Krolewska
00-060 Warsawa
Pol an d
Phone: [phone]
Fax: [phone]

JLG Industries (Sweden)
Enkopingsvagen 150
Box 704
SE - 175 27 Jarfalla
Sweden
Phone: [phone]
Fax: [phone]