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The Model 930E truck is equipped with a dry disc type
parking brake assembly mounted on each wheel motor
rotor shaft. The parking brake assemblies are inboard
mounted and can be accessed through the rear axle
housing door.
The parking brake is intended to prevent truck move-
ment after the vehicle has stopped, the engine is shut
down, and when the truck is left unattended. The
parking brake is not for use during truck loading or
dumping operations. Refer to the "Operation and Main-
tenance Manual" for additional brake system operation
instructions.
OPERATION
The parking brake is a spring applied, hydraulically
released, multiple disc type brake, actuated by the
parking brake switch mounted on the instrument panel
in the operator's cab.
FIGURE 7-1. PARKING BRAKE
INSTALLATION
(RH Shown)
1. Wheel Motor Mounting Flange
2. Wheel Motor
3. Parking Brake Assembly
4. Gear (Motor Rotor Shaft)
5. Retainer Plate
6. Capscrew & Hardened
Washer
7. Park Brake Supply Hose
8. Cooling Air Duct Mount
9. Capscrew & Lockwasher
J07010 12/98
PARKING BRAKE
When the parking brake switch is placed in the ON
position, the parking brake solenoid valve (SV2) lo-
cated on the brake manifold in the hydraulic compo-
nents cabinet is de-energized, removing hydraulic
pressure from the parking brake assemblies. Internal
belleville springs in the park brake assemblies act on
the piston to compress the disc pack, preventing rota-
tion of a gear (4, Figure 7-1) mounted on the wheel
motor rotor shaft.
When the parking brake is switched to the OFF posi-
tion, pressurized oil is supplied to the brake assemblies
through the (energized) parking brake solenoid valve.
Oil pressure applied to the parking brake piston com-
presses the belleville springs, releasing the discs to
allow the wheel motor rotor gear to rotate.
System interlocks prevent application of the parking
brake if the truck is in motion.
Parking Brake
J7-1
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Troubleshooting
