Brake Drum Replacement

4-40. Brake Drum Replacement

(2) Inspect brake drum for cracks, scoring or

other damage.

a. Remove hub and brake drum as per paragraph

4-38 d. (1) (2) (3) and (4).

b. Adjustment. The trailer is equipped with a

b. On inside of brake drum loosen and remove 6

straight-air system of the cam type brake. Each cam

bolts securing brake drum to wheel and hub. (fig. 4-4).

brake is actuated by a brake chamber which forces a

c. Replace brake drum and assemble in reverse

slack adjust er lever to rotate the cam shaft. The cam at

order.

the outer end of the cam shaft acting on a cam follower

pushes the brake lining out against the brake drum.

4-41. Brake Shoe and Assembly Inspection, Brake

Wheel bearings should be properly adjusted before

Adjustment

making brake adjustment.

a. Inspection. Periodic adjustment, cleaning and

(1) Have the wheel raised off the ground.

lubrication of brake equipment should be established

by the organizational maintenance on the basis of past

(2) With the wheel turning slightly (by hand)

experience and severity of operation. Linings and

rotate the adjusting screw (worm shaft) on the slack

drums are parts particularly subject to wear.

adjuster (note worm shaft lock must be depressed) until

compensate for this wear brakes should be adjusted as

the wheel is locked by the brakes. (fig. 4-10).

frequently as required to maintain satisfactory operation

(3) Back off the adjusting screw until the

and maximum safety. Brakes should be cleaned,

wheel turns freely with no evidence of brake drag.

inspected, lubricated and adjusted each time the hubs

Usually two clicks of the slack adjuster screw is

are removed.

sufficient to provide the proper clearance.

(4) After adjusting brakes, if the brake will not

(1) Inspect

brake

linings

for

grease

release (cam returns to closed position) the linings

saturation, wear and loose bolts. Lining should not be

should be replaced.

allowed to wear to the point where bolts may contact

brake drums.

c. Chamber Stroke. When travel increases from

liner wear to 2 inches, readjust. (fig. 4-11).

4-24