Service Manual Owner's manual
Table Of Contents
- Section 1. Specifications
- Section 2. General
- Section 3. Chassis & Turntable
- 3.1 Tires & Wheels
- 3.2 Wheel Drive Assembly, 2WD
- 3.3 Drive Motor - 2WD (Prior to S/N 83331)
- 3.4 Drive Motor (S/N 83331 to Present)
- 3.5 Torque Hub
- 3.6 Wheel Drive Assembly, 4WD
- 3.7 Torque Hub (4WD Machines W/ Integral Brake)
- Roll, Leak and Brake Testing
- Tightening and Torquing Bolts
- Main Disassembly
- Input Carrier Disassembly
- Output Carrier Disassembly
- Housing-Spindle Disassembly
- Spindle-Brake Disassembly
- Input Carrier Sub-Assembly
- Output Carrier Sub-Assembly
- Spindle-Brake Sub-Assembly
- Housing-Spindle Sub-Assembly
- DW2B Integral Brake Check
- Main Assembly
- 3.8 Drive Brake, 2WD - Mico (Prior to S/N 83331)
- 3.9 Re-Aligning torque hub input coupling
- 3.10 Oscillating Axle Bleeding Procedure and Lockout Test
- 3.11 Swing Drive Hub
- 3.12 Swing Brake - Mico (Prior to S/N 66417)
- 3.13 Swing Motor (Prior to S/N 66417)
- 3.14 Swing Motor (S/N 66417 to Present)
- 3.15 Procedure For Setting Gear Backlash
- 3.16 Swing Bearing
- 3.17 Rotary Coupling
- 3.18 Generator
- 3.19 Ford EFI Engine
- 3.20 Deutz EMR 2 (S/N 85332 to Present)
- 3.21 GM Engine General Maintenance
- 3.22 GM Engine Dual Fuel System
- Fuel Filter
- Electric Lock Off
- EPR Assembly
- Low Pressure Regulator (LPR)
- Air Fuel Mixer
- Electronic Throttle Control (ETC)
- Engine Control Module
- Heated Exhaust Gas Oxygen Sensor
- Gasoline Multi Point Fuel Injection System (MPFI)
- Gasoline Fuel Pump
- Gasoline Pressure And Temperature Sensor Manifold
- Fuel Filter
- Fuel Injector Rail
- Fuel Injector
- 3.23 GM Engine Fuel System Repair
- Propane Fuel System Pressure Relief
- Propane Fuel System Leak Test
- Propane Fuel Filter Replacement
- Electronic Pressure Regulator (EPR) Assembly Replacement
- Temperature Manifold Absolute Pressure (TMAP) Sensor
- Electronic Throttle Control Replacement
- Mixer Replacement
- Coolant Hose Replacement
- Vapor Hose Replacement
- Engine Control Module Replacement
- Heated Exhaust Gas Oxygen Sensor Replacement
- 3.24 GM Engine LPG Fuel System Diagnosis
- Section 4. Boom & Platform
- Section 5. Hydraulics
- Section 6. JLG Control System
- Section 7. Basic Electrical information & schematics
SECTION 4 - BOOM & PLATFORM
3121139 – JLG Lift – 4-51
Troubleshooting
Table 4-1. Troubleshooting
Problem Cause Solution
1. Shaft rotates slowly or not at all a. Insufficient torque output
b. Low rate of fluid flow
c. Control or counterbalance valve has internal
leak
d. Piston and/or shaft seal leak
e. Corrosion build-up on the thrust surfaces
f. Swollen seals and composite bearings caused
by incompatible hydraulic fluid
a. Verify correct operating pressure. Do not
exceed OEM’s pressure specifications. Load may
be above maximum capacity of the actuator.
b. Inspect ports for obstructions and hydraulic
lines for restrictions and leaks.
c. Disconnect hydraulic lines and bypass valve.
Leave valve ports open and operate the actuator
through housing ports (do not exceed OEM’s
operating pressure). The valve must be replaced if
a steady flow of fluid is seen coming from the valve
ports.
d. Remove the plug and the housing’s valve ports.
Operate the actuator through the housing ports.
Conduct the internal leakage test as described in
the Testing section on page 24 of this manual.
e. Re-build the actuator. Remove all rust then pol-
ish. Replacement parts may be needed.
f. Re-build the actuator. Use fluid that is compati-
ble with seals and bearings.
2. Operation is erratic or not responsive a. Air in actuator a. Purge air from actuator. See bleeding proce-
dures.
3. Shaft will not fully rotate a. Twisted or chipped gear teeth
b. Port fittings are obstructing the piston
a. Check for gear binding. Actuator may not be
able to be re-built and may need to be replaced.
Damage could be a result of overload or shock.
b. Check thread length of port fittings. Fittings
should during stroke not reach inside the housing
bore.
4. Selected position cannot be maintained a. Control or counterbalance valve has internal
leak
b. Piston and/or shaft seal leak
c. Air in actuator
a. Disconnect hydraulic lines and bypass valve.
Leave valve ports open and operate the actuator
through housing ports (do not exceed OEM’s
operating pressure). The valve must be replaced if
a steady flow of fluid is seen coming from the valve
ports.
b. Remove the plug and the housing’s valve ports.
Operate the actuator through the housing ports.
Conduct the internal leakage test as described in
the Testing section on page 24 of this manual.
c. Purge air from actuator. See bleeding proce-
dures