JLG 740A, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3-2 – JLG Lift – 3121160
3. The tightening of the nuts should be done in stages.
Following the recommended sequence, tighten nuts
per wheel torque chart.
4. Wheel nuts should be torqued after first 50 hours of
operation and after each wheel removal. Check
torque every 3 months or 150 hours of operation.
3.2 OSCILLATING AXLE BLEEDING
PROCEDURE AND LOCKOUT TEST
Lockout Cylinder Bleeding
To start the test, the axle must be fully oscillated in one
direction. Start with oscillating the axle so that the left lock-
out cyl. is fully retracted (left front tire up), and the right
lock-out cyl. Is fully extended (right front tire down).
ENSURE PLATFORM IS FULLY LOWERED AND BOOM IS CEN-
TERED OVER REAR AXLE PRIOR TO BEGINNING BLEEDING PRO-
CEDURE. MAKING SURE MACHINE IS ON A LEVEL SURFACE AND
REAR WHEELS ARE BLOCKED, BRAKE WIRE IS DISCONNECTED.
1. Making sure machine is on a level surface and rear
wheels are blocked, brake wire is disconnected.
2. Center boom over rear axle making sure that cam
valve is depressed.
NOTE: To oscillate the axle, the lock-out valve plunger must
be depressed.
3. Using a Phillips screwdriver, remove screw from
connection on the brake valve and remove connec-
tor as shown.
4. Use suitable container to retain any residual hydrau-
lic fluid, place container under the lockout cylinder.
5. With the left lock-out cyl. retracted, open the bleeder
on top of the cylinder, then have an operator from
the platform (on high engine) feather drive. Activate
drive just enough so the engine is under load but
not enough to stall the engine.
6. Close the bleeder when there is a steady stream of
oil and not air.
7. With the axle in the same position, go to the right
lock-out cyl. and open the bleeder at the rod end.
Activate drive in the same manner and close when
all air has been purged.
8. Close the bleeder when there is a steady stream of
oil and not air.
9. Oscillate the axle the other direction, left lock-out cyl.
extended (tire down), right lock-out cyl. retracted
(tire up). Use the same procedure for the bleeder in
the rod end of the left lock-out cyl., Then the piston
end of the right lock-out cyl. then close.
10. Repeat this process one more time to ensure that all
air has been purged from the system.
11. Perform oscillating axle lockout test.
12. If necessary, repeat steps 1 thru 9.
13. Reinstall the brake wires. See Figure 3-2.
NOTE: Bleeding of the oscillating axles is an infrequent
operation performed after hydraulic line failure and or
lock-out cylinder repair.
Table 3-1. Wheel Torque Chart
TORQUE SEQUENCE
1st Stage 2nd Stage 3rd Stage
70 ft. lbs.
(95 Nm)
170 ft. lbs.
(225 Nm)
300 ft. lbs.
(405 Nm)
Figure 3-1. Oscillating Valve Adjustment.
Figure 3-2. Brake Valve Wiring Connection.