Gradall 534B (9020-7317) Service Manual - Manual (Page 18)

To Engage Rear Driving Hubs: Repeat procedure.
NOTE: If machine is moved with keeper pin plate
removed, input shaft pin will pop out.
Hydraulic flow to rear axle drive motors is
controlled electrically. An automatic reset type
breaker is included to prevent damage from
overload.
If circuit breaker trips (opens) rear
axle drive will be inoperative for approximately
ten seconds until breaker resets. Notify
maintenance personnel if circuit breaker trips
repeatedly.
To determine whether circuit breaker has tripped,
attempt to move machine using inching travel. If
machine does not respond to inching travel pedal
circuit breaker is open.
Inching Travel
Inching travel is provided to permit very slow travel
while maintaining high engine speed for other
functions. Because inching travel depends on
hydraulic flow to rear axle drive motors, inching
travel functions only in first and second gears. There
is no hydraulic flow to drive motors in third gear.
Inching travel is controlled by the service
brake/inching travel pedal. This pedal has three
separate functions:
Rear Driving Axle
The rear driving axle includes planetary hubs which
are powered by hydraulic motors mounted on the
inner face of the hubs. Hydraulic flow to drive
motors is provided only in first and second gear
speed ranges. Drive motors are free-floating in third
gear.
Continuous driving for two miles or more
in third gear, with rear driving hubs
engaged, can damage hydraulic drive
motors.
To Disengage Rear Driving Hubs:
Apply parking brake and remove key from
ignition switch.
Remove thumb screws from keeper pin plate.
Remove and rotate plate per photo on pg. 6 (cup
out - engaged - cup in - disengaged).
Secure plate using thumb screws.
Repeat procedure for other hub.
1.
2.
3.
4.
5.
It disconnects front drive axle from
transmission.
It controls hydraulic flow to rear axle drive
motors (hydraulic flow equals speed).
It applies service brake.
1.
2.
3.
As illustrated, the three functions occur in sequence
as pedal is depressed from top to bottom of stroke.
To Engage Inching Travel:
Practice inching/braking in a safe, open
area until you are thoroughly familiar with
response of machine to pedal travel
1.
2.
3.
Depress service brake/inching travel pedal
approximately 1-1/2 inches to disengage front
driving axle from transmission. At this point rear
drive motors are receiving full flow and travel
speed will not have changed.
Continue to depress pedal to reduce speed - the
more pedal travel, the less speed.
To stop, depress pedal fully.
OR
To resume normal travel release service brake/
inching travel pedal. Depress accelerator pedal to
attain appropriate speed.
1 2