Gradall 534B (9103-1390) Service Manual - Manual (Page 23)

General
The brake system furnished on the handler includes a
service brake, inching brake and parking brake.
Because service braking and “inching” (slow travel)
functions overlap, some features of inching will be
discussed here. Refer to Drive Train Section for
additional information on inching travel.
Inching Travel
Overlap between service braking and inching occurs
because the same foot pedal controls both functions,
and also because both functions control travel speed.
However, the methods of controlling travel speed are
quite different: service braking involves a controlled
stopping force applied to the front wheels while,
inching involves a controlled driving force applied to
the rear wheels.
The service brake/inching pedal has three separate
functions:
As illustrated, the three functions occur in sequence
as service brake/inching pedal is depressed from top
to bottom of stroke.
Practice inching/braking in a safe, open
area until you are thoroughly familiar with
response of machine to pedal travel.
BRAKE SYSTEM
Service Brakes
The service brake is applied to the front wheels of the
handler.
Oil for the brakes comes from the pilot circuit pump,
thru an accumulator charging valve and the accumu-
lator. When the service/inching brake pedal is de-
pressed far enough to actuate the brake valve, the
hydraulic oil flows to the wet disc brakes in both front
wheel hubs. The pressure compresses the brake discs.
Parking Brakes
The parking brakes are also applied at the wet disc
brakes in the front axles.
TO APPLY THE PARKING BRAKE, pull up on the
parking brake knob located to the left of the oper-
ator’s seat. This opens the parking brake circuit to
dump, allowing a spring in the wet disc brake
assembly to compress the discs, applying the brakes.
TO RELEASE THE PARKING BRAKE, push down
on the parking brake knob.
When the handler is not being used, with the engine
shut off, the parking brakes must be applied.
It disconnects front drive axle from transmission.
It controls hydraulic flow to rear axle drive motors
(hydraulic flow regulates speed).
It applies service brake.
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