JLG 80HX_HX+6_HXER ANSI Service Manual - Manual (Page 78)

SECTION 3 - CHASSIS & TURNTABLE
3-40 – JLG Lift – 3120271
3.13 OSCILLATING AXLE BLEEDING
PROCEDURE
Lockout Cylinder Bleeding (Without Holding
Valves)
1. Make a hydraulic hose using approximately 6 feet of
1/4 in. wire braid hose with quick connect fitting on
one end and a 1/4 in. JIC female fitting on the other.
2. Swing the boom over the front of the machine and
engage the turntable lock. Using ground control
raise the boom out of the way.
3. Remove the cover between frame slabs through
which the cam valve wheel protrudes.
4. Remove cap from fitting on cam valve and connect
your hose (see 1 above) at this point.
5. Attach the other end of the hose to the quick con-
nect on the swing brake.
6. Using a floor jack (or overhead crane) raise one
front wheel approximately 6 inches (15.2 cm) off the
ground.
7. Use a bar as a lever to press down on the cam valve
plunger which will allow the axle to fully oscillate
against the stop.
8. With the aid of an assistant, start the engine from
ground control.
ENSURE TURNTABLE LOCK IS ENGAGED.
9. While your assistant activates swing from ground
control, depress plunger on cam valve and open
both bleeders on the lockout cylinder of the elevated
wheel purging any air.
10. Remove the jack from the elevated wheel and, using
the bar, again press down on the cam valve plunger,
allowing the axle to center.
11. Next raise the other front wheel as you did in step 6
and repeat steps 7 thru 10.
12. Shut down the engine, remove the hose, and
replace the cap on the cam valve fitting. Install frame
cover over cam valve and disengage turntable lock.
13. The boom can now be returned to its normal posi-
tion.
Lockout Cylinder Bleeding (With Holding
Valves)
ENSURE PLATFORM IS FULLY LOWERED AND BOOM IS CEN-
TERED OVER REAR AXLE PRIOR TO BEGINNING BLEEDING
PROCEDURE.
MAKING SURE MACHINE IS ON A LEVEL SURFACE AND REAR
WHEELS ARE BLOCKED, DISENGAGE DRIVE HUBS. OPTIONAL
4WD ALL HUBS MUST BE DISENGAGED.
1. Making sure machine is on a level surface and rear
wheels are blocked, disengage drive hubs. Optional
4WD all hubs must be disengaged.
2. Make up an adapter with an air regulator, remove
filler cap on hydraulic tank and install regulator.
3. Attach air supply to the regulator and set regulator to
2 - 5 psi (0.14-0.34 Bar).
DO NOT EXCEED 5 PSI (0.34 BAR) INTO HYDRAULIC TANK.
MORE THAN 5 PSI (0.34 BAR) WILL CAUSE DAMAGE TO THE
HYDRAULIC TANK.
4. Activate machine hydraulic system from platform
control station.
5. Place LOW ENGINE, HIGH DRIVE SPEED and HIGH
WHEEL MOTOR SPEED control switches to their
respective HIGH positions.
6. Depress footswitch and activate DRIVE CONTROL-
LER to “FORWARD” position.
7. Using a suitable lifting equipment lift front of
machine and place a 6 in. (15.2 cm) high block
under right front wheel.
8. Lower machine so both of the lockout cylinders are
oscillated; one extended, the other retracted.
9. Use suitable containers to retain any residual
hydraulic fluid, place containers under each lockout
cylinder.
10. With DRIVE CONTROLLER activated and engine at
idle, open all four bleeder screws (two on each lock-
out cylinder), one at a time, then close bleeder
screws when all air is dissipated (bled).
11. Using a suitable lifting equipment lift front of
machine and remove the 6 in. (15.2 cm) high block.
12. Transfer the 6 in. (15.2 cm) high block to the left front
wheel and repeat steps 2 thru 7, substituting the
word “right” for “left” in step 5.
13. Perform oscillating axle lockout test.