JLG issued document 3120672 as the factory service book for the 40HA aerial platform, and this 105-page JLG 40HA service manual PDF is that publication, unaltered. Electrical diagrams trace every circuit on the machine, while the troubleshooting section, roughly a third of the book, works through hydraulic circuit checks fault by fault. Between those sit cylinder repair, boom maintenance, swing bearing wear tolerances, drive torque hub rebuilds, and the pressure setting procedures your annual inspection leans on. Set the Sepac swing brake at 1500 PSI (103.4 Bar), run the wheel lugs to 80 ft. lbs. (109 Nm), and pull anything else from the torque chart up front. A boom lift parked over a mystery fault earns nothing. Print whatever page the job calls for and let it get greasy on the bench; bookmarks and a real text layer get you to it fast.
What's Inside This JLG 40HA Manual
| System | Pages | Key Topics |
|---|---|---|
| List of Illustrations | 4 | Torque Chart, Lubrication Chart, Boom Prop Configurations |
| List of Tables | 5-6 | Hydraulic Oil, Lubrication Specifications, Cylinder Specifications, Component Weights, Stability Weights, Troubleshooting Tables |
| Specifications | 7-16 | Capacities, Component Data, Performance Data, Torque Requirements, Lubrication, Pressure Settings, Cylinder Specifications, Major Component Weights |
| General Maintenance Guidelines | 17-19 | Safety, Cleanliness, Component Removal, Lubrication, Battery Maintenance |
| Cylinder Theory and Repair | 20-28 | Cylinder Theory, Cylinder Checking Procedures, Cylinder Repair, Cylinder Removal and Installation |
| Boom Maintenance | 29-31 | Boom Removal, Boom Disassembly, Boom Inspection, Boom Assembly, Tilt Alarm Switch |
| Engine Throttle and Pressure Settings | 32-38 | Throttle Checks, Governor Adjustments, Pressure Setting Procedures, Control Valves |
| Swing Bearing Maintenance | 39-43 | Swing Bearing Wear Tolerance, Swing Bearing Replacement, Devcon Application, Swing Bearing Torque Values |
| Drive Torque Hub and Brake Maintenance | 44-67 | Drive Torque Hub Disassembly, Drive Torque Hub Assembly, Swing Brake Maintenance, Drive Brake Maintenance, Dual Fuel System |
| Preventive Maintenance Schedule | 68-70 | Inspection Codes, Annual Inspection |
| Troubleshooting | 71-105 | General, Troubleshooting Information, Hydraulic Circuit Checks |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Bearing To Chassis | 110 FT. LBS. (149 Nm) | p. 9 |
| Bearing To Turntable | 220 FT. LBS. (298 Nm) | p. 9 |
| Swing Brake - Ausco (Machines Built Prior to August 1991) | 1500 PSI (103.4 Bar) | p. 14 |
| Swing Brake - Sepac (Machines Built From November 1992 to Present) | 1500 PSI (103.4 Bar) | p. 14 |
| Ford VSG411 engine speed (High) | 3000 RPM | p. 32 |
| Ford VSG411 engine speed (LOW) | 2200 RPM | p. 32 |
| Drive Hub Lubricant Capacity | 17 ounces | p. 7 |
| Ford LSG-411 Engine Oil Capacity (w/Filter) | 3.40 Quarts | p. 7 |
| Deutz F2L1011 Engine Oil Capacity (w/Filter) | 6.90 Quarts | p. 7 |
| Kubota V1200-B Engine Oil Capacity (w/Filter) | 6.0 Quarts | p. 7 |
| Main Relief Pressure (Standard Controls) | 3000 PSI | p. 14 |
| Swing Relief Pressure | 1500 PSI | p. 14 |
JLG 40HA Common Problems This Manual Covers
JLG 40HA drive engages and engine revs with joystick but machine will not move either direction
Check battery voltage and ground cables first; low system voltage blocks the drive command and sets code 441. Wiggle harness connectors at the drive controller while an assistant holds the joystick, then trace the circuit on the wiring diagram on page 91. Verify main relief pressure reaches 3000 PSI before condemning the controller.
Manual Section: Chassis Assembly TroubleshootingBoom will not come down from height, lift function feels hydraulically locked in place
Inspect the safety valves in the lift circuit; a stuck valve traps oil and locks the boom in the air. Support the platform before opening anything. Follow the cylinder checking procedures starting on page 22 to test for internal leakage, and confirm main relief pressure is set at 3000 PSI before replacing any valve.
Manual Section: Boom Assembly TroubleshootingBoom swing weak or completely dead in both directions while other functions work normally
Test swing relief pressure first; it should hold 1500 PSI (103.4 Bar). If pressure is good, pull the swing brake and check that it releases fully; a dragging brake mimics a bad swing motor. Follow the swing brake procedures starting on page 44 and torque the swing motor to brake bolts to 75 ft. lbs. (102 Nm) on reassembly.
Manual Section: Drive Torque Hub and Brake Maintenance p. 44Engine speed stuck at low idle, RPM does not change when joystick is moved
Check the governor linkage for wear and loose adjustment before replacing the actuator. Run the throttle checks on page 32: low speed should hold 2200 RPM and high speed 3000 RPM. If the speeds will not adjust to spec, verify controller power and the speed signal wiring back to the actuator.
Manual Section: Engine Throttle and Pressure Settings p. 32Functions cut out intermittently, fault codes 441 or 445 return after battery replacement
Clean and tighten every ground cable and harness connector, then wiggle-test each with the function live and watch for dropout; corroded pins cause most repeat faults. If codes 441 or 445 return, measure charging voltage at the battery with the engine at its 2200 RPM low-speed setting, then trace suspect circuits on the wiring diagram on page 91.
Manual Section: Electrical System Troubleshooting p. 91Frequently Asked Questions
What are the torque specifications for JLG 40HA wheel lugs and boom bolts?
The torque specification for wheel lugs is 80 ft. lbs. (109 Nm). For the bearing to chassis bolts, the torque is 110 ft. lbs. (149 Nm), and for the bearing to turntable bolts, it is 220 ft. lbs. (298 Nm). p. 9
What is the hydraulic oil capacity for the JLG 40HA?
The hydraulic oil tank capacity is 50 U.S. Gallons (189.1 l) with 10% air space. The total hydraulic system capacity, including the tank, is 60 U.S. Gallons (227.12 l). p. 7
How often should the hydraulic filter be replaced on the JLG 40HA?
JLG Industries recommends replacing the hydraulic filter after the first 40 hours of operation and every 250 hours thereafter. p. 13
What is the procedure for bleeding the oscillating axle lockout cylinders on machines built from April 1993 to present?
Ensure the platform is lowered and centered. With the machine on a level surface, disengage drive hubs, install an air regulator on the hydraulic tank set to 2-5 psi (0.14-0.34 Bar), and open the four bleeder screws (two on each cylinder) one at a time until air is dissipated. p. 65
What is the torque specification for the basket rotator brake on a JLG 40HA?
The belleville washers for the basket rotator brake should be torqued to 140 ft. lbs. (190 Nm). p. 66
Will this JLG 40HA Service Manual download right away?
All 105 pages arrive as one searchable PDF at checkout. Read it at the desk, then take the phone out to the machine.
Can I print a copy of this JLG 40HA Service Manual for the shop?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
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