Brake Interlock Switch

TM 10-3930-628-12

(3) Tighten switch mounting screws to secure

adjustment.

Removal. To remove interlock switch (5, fig.

4-17), disconnect wires (1 and 4) and remove two

mounting screws (8), nuts (20) and lock washers (9).

d. Installation. Install interlock switch (5, fig.

4-17) and secure with two screws (8), nuts (20) and lock

washers (9). Connect wires (1I and 4) to switch. Adjust

switch operation ( b above).

4-36. Service Brake Brake Shoes

a. General. The service brake brake shoes

are mounted behind the dust shield. The shoes are

attached to the wheel cylinders and return springs. The

brakes are self-adjusting.

b. Removal.

(1) Refer to paragraph 4-39 and remove the

front drive wheel and tire assembly.

(2) Refer to figure 4-19 and remove brake dust

shield as follows:

(a) Remove four screws and lock washers

securing dust shield to axle. Remove wheel bearing

from axle.

(b) Carefully remove dust shield from around

Figure 1-18. Service brake system bleeder screw.

axle pinion.

(3) Repeat Open the bleeder screw one turn.

(4) Slowly depress brake pedal to end of travel

and release pedal. Repeat several times. Observe

Cause in jar and repeat pumping of brake pedal until no

air bubbles escape from hose. Hold pedal at bottom of

travel and close bleeder screw to keep additional air from

entering system.

Note. While pumping pedal check fluid level in

master cylinder. Add fluid to keep cylinder as close to

full as possible at all times

(5) Close bleeder screw and disconnect hose.

Repeat operation on bleeder screw on other front wheel.

(6) Fill master cylinder to proper level after

bleeding operation. Replace filler.

Caution: Discard fluid salvaged from brake

system during bleeding operation. Do not use in system.

4-35. Brake Interlock Switch

a. General. The brake switch is operated by a

switch actuator (17, fig. 4-17) Brake pedal should move

about one inch before switch is opened. Depress brake

pedal and check switch operation. If adjustment is

necessary, adjust as follows:

b. Adjustment.

(1) Loosen switch mounting screws (8, fig.

4-17)

(2) Slide switch toward rear of truck to shorten

pedal travel before switch action or toward front of truck

Figure 4-19. Service brake dust shield, installed view.

to lengthen pedal travel.

4-20