Section II. SERVICE BRAKES

TM 10-3930-631-34

Assembly.

(1) Install brake disk (5, fig. 4-1) on shaft of

drive motor. Secure brake disk with nut (35, fig. 4-3) and

(1) Install stator pads (7 and 8, fig. 4-2) in

washer (36).

secondary bracket (5).

(2) Install brake caliper (4, fig. 4-1) on drive

(2) Install secondary bracket on bracket (4).

motor housing and secure with screws (6, fig. 4- 3).

Install screws (1), washers (2) and nuts (3) to secure

Install washer (7) between caliper and motor.

parts. Do not tighten nuts.

(3) Install shoulder screw (1, fig. 4-1)

(3) Insert disk (37) between stator pads.

through actuating lever (7). Secure with washer and lock

(4) Tighten lock nuts (3) until stator pads almost

nut.

make contact with disk but disk still moves freely

(4) Refer to TM 10-3930-631-12 and to install

between stators. Remove disk.

d. Installation.

and adjust brake linkage

Section II. SERVICE BRAKES

pressure. This pressure closes the switches. One

4-3. Description

switch operates the stop and taillight mounted at the rear

a. The hydraulic service brake system is of the full-

of the operator's seat to indicate the truck is stopping.

floating, self-centering, self-adjusting type. Main

The other switch is an interlock switch. When it is

components of the system are the brake pedal and

closed, current is bypassed from the potentiometer in the

linkage, master cylinder, wheel cylinders and brake

speed control box. Current to the control circuit module

assembly.

is cut off, no current is supplied to the drive motor and

b. The mechanically actuated master cylinder

power movement is halted.

transmits hydraulic pressure through heavy duty brake

4-4. Brake Pedal and Linkage

lines to wheel cylinders. The wheel cylinders are of the

a. Removal.

double ended type, with actuating links extending from

each end. The links transmit movement from the

CAUTION

cylinders to the brake shoes.

Before attempting any removal procedures,

c. The top of each shoe rides freely in a wear plate

disconnect battery receptacle and discharge

while the bottom of the shoe is engaged by the wheel

capacitors.

cylinder link.

(1) Remove floor and toe plates to gain access

d. Wear adjustment of brake linings is made

to brake pedal and linkage.

automatically in normal use by the self-adjusting

(2) Refer to TM 10-3930-631-12 and remove

mechanism. The shoes are held against the brake wear

brake master cylinder.

plates, wheel cylinder links, and adjusting assemblies by

(3) Refer to paragraph 3-9 disconnect and

tension springs which maintain the shoes in balance.

remove brake lines from cylinder and wheels.

e. Two switches, actuated by hydraulic pressure,

(4) Remove cotter pin (9, fig. 4-4) and clevis pin

are mounted on the front of the master cylinder. The

(10) to disconnect clevis (11) from brake pedal.

switches are normally open. When the brake pedal is

depressed the master cylinder delivers hydraulic

4-5