Service Manual Instruction Manual
Table Of Contents
- Section A. Introduction - Maintenance Safety Precautions
- Section 1. Specifications
- Section 2. General
- Section 3. Chassis & Turntable
- 3.1 Tires And Wheels
- 3.2 Torque Hub
- Oil Information
- Roll and Leak Testing
- Tightening and Torquing Bolts
- Main Disassembly
- Output Carrier Disassembly
- Input Carrier Disassembly
- Hub-Spindle Disassembly
- Spindle-Brake Disassembly
- Cover Disassembly
- Cover Assembly
- Input Carrier Sub-Assembly
- Output Planet Gear Sub-Assembly
- Spindle - Brake Sub-Assembly
- Hub-Spindle Sub-Assembly
- Cover Sub-Assembly
- Main Assembly
- Integral Brake Check
- 3.3 Free Wheeling Option
- 3.4 Drive Motor
- 3.5 Oscillating Axle Bleeding Procedure and Lockout Test
- 3.6 Steer Adjustments
- 3.7 Swing Drive
- 3.8 Swing Bearing
- 3.9 Swing Brake - Mico
- 3.10 Rotary Coupling
- 3.11 Generator
- 3.12 Deutz D2.9 L4 Engine
- 3.13 Deutz D2011 Engine
- 3.14 Spark Arrester Cleaning Instructions
- 3.15 Glow Plugs
- 3.16 Deutz EMR 2
- 3.17 Bio Fuel in Deutz Engines
- 3.18 GM Engine General Maintenance
- 3.19 GM Engine Dual Fuel System
- Fuel Filter
- Direct Electronic Pressure Regulator (DEPR)
- Air Fuel Mixer
- Electronic Throttle Control (ETC)
- Electric Lock Off
- Engine Control Module (ECM)
- 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
- 3.20 GM Engine Fuel System Repair
- Propane Fuel System Pressure Relief
- Propane Fuel System Leak Test
- Propane Fuel Filter Replacement
- Direct Electronic Pressure Regulator (DEPR) Maintenance And Inspection
- Check/Drain Oil Build-Up In 2-Stage Vaporizer
- Air Fuel Mixer/Throttle Control Device Maintenance And Inspection
- Exhaust System And Catalytic Converter Inspection And Maintenance
- Temperature Manifold Absolute Pressure (TMAP) Sensor
- Throttle Body (ETC) Replacement
- Mixer Replacement
- Electronic Pressure Regulator (EPR) Replacement
- Regulator Replacement
- Coolant Hose Replacement
- Vapor Hose Replacement
- Engine Control Module Replacement
- Heated Exhaust Gas Oxygen Sensor Replacement
- 3.21 GM Engine LPG Fuel System Diagnosis
- Section 4. Boom & Platform
- Section 5. Hydraulics
- 5.1 O-Ring Lubrication
- 5.2 Cylinders - Theory of Operation
- 5.3 Cylinder Checking Procedure
- 5.4 Cylinder Removal and Installation
- Cylinder Locations
- Main Boom Telescope Cylinder Removal
- Main Boom Telescope Cylinder Installation
- Main Boom Lift Cylinder Removal
- Main Boom Lift Cylinder Installation
- Upright Level Cylinder Removal
- Upright Level Cylinder Installation
- Tower Boom Lift Cylinder Removal
- Tower Lift Cylinder Installation
- Tower Telescope Cylinder Removal
- Tower Telescope Cylinder Installation
- 5.5 Hydraulic Cylinder repair
- Tower Boom Lift Cylinder
- Cleaning and Inspection
- Assembly
- Upright Level Cylinder
- Cleaning and Inspection
- Assembly
- Master Cylinder
- Cleaning and Inspection
- Assembly
- Main Boom Lift Cylinder
- Cleaning and Inspection
- Assembly
- Main Boom Telescope Cylinder
- Cleaning and Inspection
- Assembly
- Tower Boom Telescope Cylinder
- Cleaning and Inspection
- Assembly
- Platform Level (Slave) Cylinder
- Cleaning and Inspection
- Assembly
- Jib Lift Cylinder (AJ Only)
- Cleaning and Inspection
- Assembly
- Steer Cylinder
- Cleaning and Inspection
- Assembly
- Axle Lockout Cylinder
- 5.6 Hydraulic Pump (Gear)
- 5.7 Variable Pump
- 5.8 Hydraulic Component Start-Up
- 5.9 Pressure Setting Procedures
- Section 6. JLG Control System
- Section 7. Basic Electrical Information & Schematics

SECTION 5 - HYDRAULICS
5-44 – JLG Lift – 3121616
Assembly
NOTE: Use proper cylinder seal kit for cylinder assembly. See your
JLG Parts Manual.
Apply a light film of hydraulic oil to all components before
assembly.
1. Use seal tool to install new rod seal into applicable cylin-
der head gland groove.
Figure 5-92. Rod Seal Installation
IMPROPER SEAL INSTALLATION CAN CAUSE CYLINDER LEAKS AND IMPROPER
CYLINDER OPERATION. ENSURE ‘POLY-PAK’ PISTON SEALS ARE PROPERLY
INSTALLED. REFER TO WIPER SEAL INSTALLATION FOR CORRECT SEAL ORIEN-
TATION.
2. Use a soft mallet to tap new wiper seal into applicable
cylinder head gland groove. Install new wear ring in
applicable cylinder head gland groove.
Figure 5-93. Poly-Pak Piston Seal Installation
Figure 5-94. Wiper Seal Installation
3. Place new O-ring and back-up seal in applicable outside
diameter groove of cylinder head.
Figure 5-95. Head Seal Kit Installation
4. Install washer ring on rod. Carefully install head gland
on rod. Do not damage or dislodge wiper and rod seals.
Push head along rod to rod end, as applicable.
5. Carefully slide piston spacer on rod.
NOTE: Upper telescope cylinder piston has an O-ring installed
inside spacer.
ROD SEAL
SEAL TOOL
1" #7004275
1 1/2" #7004276
2" #7002826
CYLINDER
HEAD
1
O-Ring
Backup Ring
Cylinder Head