JLG 680S Service Manual - Manual (Page 110)

SECTION 3 - CHASSIS & TURNTABLE
3-62 – JLG Lift – 3121234
3.8 RE-ALIGNING TORQUE HUB INPUT
COUPLING
The following procedure applies to torque hubs with inte-
gral brakes.
Equipment Required
1. Hydraulic power supply (hand pump) capable of
producing 200 psi (13.8 bar).
2. Hydraulic fittings to adapt hydraulic supply to brake
release port on hub.
Procedure
1. Using appropriate fittings, connect a line from the
hydraulic power supply to the brake port.
2. Pressurize the brake release port 155 to 200 psi
(10.6 to 13.8 bar) to release the brake.
3. Verify that the brake is released by rotating the input
coupling or hub spindle.
4. Once the brake is released, the input coupling will
be free to re-align with the drive motor.
5. Install the drive motor on the hub, then release the
hydraulic pressure at the brake release port. The
coupling will remain in position.
6. Disconnect the hydraulic power supply and recon-
nect the line going into the brake release port.
3.9 OSCILLATING AXLE BLEEDING
PROCEDURE AND LOCKOUT TEST
Lockout Cylinder Bleeding
ENSURE PLATFORM IS FULLY LOWERED AND BOOM IS CEN-
TERED OVER REAR AXLE PRIOR TO BEGINNING BLEEDING
PROCEDURE.
ENSURE MACHINE IS ON A LEVEL SURFACE AND REAR
WHEELS ARE BLOCKED, BRAKE WIRE IS DISCONNECTED.
1. Make sure machine is on a level surface.
2. Center boom over rear axle to make sure the cam
valve in the rotary coupling is depressed.
3. Place chocks under the tires to ensure the machine
does not move. Disable the machine brakes by dis-
connecting the brake solenoid on the dual select
valve.
4. Use suitable containers to catch any excess hydrau-
lic fluid. Place the containers under each lockout cyl-
inder.
5. Open one bleeder screws at a time.
6. Start the engine, position drive control lever on the
main hydraulic pump forward or reverse.
7. Close bleeder screws when all air is dissipated
(bled).
8. Reconnect the brake solenoid and remove the
wheel chocks.
9. Perform oscillating axle lockout test.
10. If necessary, repeat steps 1 thru 7.