Section XIV. MAINTENANCE OF BRAKES

TM10-3930-242-12

Section XIV. MAINTENANCE OF BRAKES

WARNING

(3) Apply brakes and hold pedal down for at

least 10 seconds. Repeat this three times, allowing

Drycleaning solvent, P-D-680, used to

30 seconds between applications.

clean parts is potentially dangerous to

(4) Release the brakes and open all four bleeder

personnel and property. Do not use near

valves. Bleed fluid from the brakes until flow stops

open flame or excessive heat. Flash point

and then close the bleeder valve.

of solvent is 138F.

(5) Repeat (3) and (4) above until no air can be

4-58. General

detected escaping from the fluid.

This section contains information for organizational

(6) Repeat the entire bleeding procedure if the

brakes show any evidence of dragging or

maintenance of the brakes.

overheating during the first few hours of operation.

4-59. Service Brakes

NOTE

Brake lines should be checked for air after

a. General. The service brakes are expander tube

the first shift of operation. If brakes do

type, hydraulically operated. Pressure is supplied

not release properly after application,

by an engine driven hydraulic pump and application

replace hydraulic tank filter. A clogged or

is controlled by an applicator valve located under

restricted filter will prevent the oil from

the operator's floor plate. The brake adjustment is

returning to the tank and therefore will

accomplished automatically by slack adjusters (fig.

not allow the brakes to release.

4-37) located in the hydraulic lines between the

applicator valve and the wheel brake assemblies.

4-60. Emergency Brake Cable and Lever

There is no manual adjustment. If a malfunction

a. Removal. Refer to figure 4-36 and remove the

occurs which cannot be corrected by the bleeding

emergency brake cable and lever.

process, report to direct support maintenance. Do

b. Cleaning and Inspection.

not attempt to repair a slack adjuster, replace it.

Lining wear can be detected by observing the arc of

(1) Clean the emergency brake cable and lever

with drycleaning solvent (item 1, App F), and dry

the brake lining retract springs. Retract springs are

thoroughly.

visible on the inboard side of the brake assembly,

(2) Inspect the cable for broken wires and kinks.

just below the outer circumference of the backing

Inspect emergency brake lever and mounting

plate. Flattened springs (with the brakes off) in-

brackets for cracks, breaks, and damaged parts.

dicate need for lining replacement. When the lining

Replace all defective parts.

is in good condition, the springs will form a shallow

arc. Check brake fluid for air after the first shift of

c. Installation. Refer to figure 4-36 and install

operation.

emergency brake cable and lever.

b. Straight Hydraulic Brake System Bleeding

d. Adjustment.

Procedure.

(1) Release emergency brake.

(1) Fill the reservoir with hydraulic oil (OE 10).

(2) Refer to figure 4-36 and remove yoke pin

NOTE

and cotter pin.

Reservoir must be free of dirt. A screen

(3) Turn yoke clockwise to tighten brake and

should be provided in the reservoir to

counterclockwise to loosen brake.

keep out foreign particles.

(4) Replace yoke pin and cotter pin.

(2) While engine is idling, open each bleeder

(5) Minor adjustment is accomplished by

valve (located on top of automatic slack adj uster fig.

turning the knurled adjusting knob which is located

4-37) and depress brake pedal until oil flows free of

at the top of the brake lever. Turn clockwise to

air. Close the bleed valves.

tighten; counterclockwise to loosen.

4-38