Section XV. MAINTENANCE OF BRAKE SYSTEM

TM 10-3930-633-12

(3) If looseness or wobble is in the wheel

(3) Bend up the tangs on the lockwasher and

bearings, remove hub cap and spindle cotter pin.

remove the outer locknut and the tabbed lock-

See figure 4-44. Tighten nut with a 12-inch

washer as shown in figure 4-45.

wrench and at the same time rotate the wheel in

(4) Apply a large socket wrench to the inner

one direction and then in the other until there is a

tube nut and tighten until drag is felt when

slight bind to be sure all bearing surfaces are in

turning the hub. (Be sure brake shoes are not

contact, Then back off the nut 1/16 to 1/4 turn

causing drag). Back off the nut slightly until the

allowing the wheel to rotate freely. Secure nut at

hub turns free and install nut lock, outer tube nut

this position with a new cotter pin and replace

and tighten. Clinch nut lock to retain nuts in this

hub cap.

position.

(5) Coat the axle shaft flange to hub mating

surface with No. 2 Permatex.

(6) Insert axle shaft in tube and rotate slowly

until splines on shaft are in registry with the

differential side gears. Push shaft in and install

the retaining nuts and tighten to 52-57 ft/lbs

torque.

Figure 4-44. Front Wheel Bearings Adjustment

d. Rear Wheel Bearings Adjustment.

(1) Refer to figure 4-45. Wheel and tire,

though not shown in the illustration, should be

left on the axle.

(2) Using the jack screw holes in the axle

shaft flange, remove axle shaft after all six nuts

Figure 4-45. Rear Wheel Bearings Adjustment

are removed from mounting studs.

Section XV. MAINTENANCE OF BRAKE SYSTEM

4-76. General

(1) Check the brake fluid level in the master

cylinder. The brake fluid should be within inch

The four wheel hydraulic brakes are of the in-

of the top. Fill with VV-B-680 Heavy Duty

ternal expanding shoe type. The brake system

Hydraulic Brake Fluid.

incorporates a tandem master cylinder where the

(2) Check the master cylinder filler cap vent

front axle brakes and the rear axle brakes are on

hole for obstructions. Vent must be open at all

separate hydraulic circuits. This arrangement

prevents complete loss of braking action in cases

times. Clean if necessary.

b. Brake Pedal Free Travel Check. A correctly

of failure at some point in the system. The

adjusted brake pedal is important so that the

operator's pedal effort is assisted by a vacuum

internal ports in the master cylinder are not

booster on the master cylinder push rod. Engine

blocked by the cylinder piston. An improperly

vacuum is used to operate the booster. Each

adjusted pedal will block the internal ports so

brake assembly provides a means for mechanical

adjustment of lining-to-drum clearance.

that upon releasing the brake pedal, fluid will be

trapped in the lines and hold the brake linings in

4-77. Inspection

contact with the brake drums. This will cause

a. Master Cylinder Fluid Level Check.

4-62