Section III. HYDRAULIC BRAKE SYSTEM

TM 10-3930-242-34

c. Disassembly. Refer to figure 57 and disas-

5-9. General

semble the brake assembly as follows:

This section contains information on the

maintenance of the hydraulic brake system.

(1) Hold the brake either vertically or hori-

T h i s includes the brake assembly, brake adjus-

zontally so that both frames (9) are exposed.

t e r , brake valve, the accumulator, and engine

(2) Place a screwdriver against the hook of

d r i v e n pump.

the retracting spring (1) and with a sharp blow,

d i s e n g a g e the spring from the frame, Drive the

5-10. Brake Assembly

s p r i n g s through the brake and out of the as-

a. General. The brake assembly on the rough

sembly.

t e r r a i n forklift is of the expander tube brake,

(3) Lift the block and shoe assembly (2) from

3 6 0 segmented, shoe-type, actuated by an ex-

t h e frame.

pander tube. Its components include a cast, tor-

(4) Remove brake frame bolts (4).

que plate upon which the expander tube is

( 5 ) Use center punch to mark upper and

mounted and an inlet connection into which the

l o w e r frames for same location on reassembly

n o z z l e of the expander tube is inserted. Steel

a n d lift upper half of frame from torque plate

s i d e frames with welded steel torque bars are

(8).

attached to both sides of the torque plate. Brake

(6) Slide expander tube (5) and inlet connec-

l i n i n g s mounted on steel shoes are inserted be-

tion (6) from the torque plate.

tween the torque bars and side frames and held

i n position by retracting springs. Steel shields

NOTE

a r e used to bridge the gap between shoes and

If expander tube is stuck to the torque plate, work

p r o t e c t the expander tube. The spring inserted

a thin piece of steel between the torque plate and

e x p a n d e r tube and draw it around the plate to

under the center of the linings and over the

free tube.

s t e e l brakeshoes withdraw the block and shoe

a s s e m b l i e s from the surface of the brakedrum

(7) Remove inlet connection from nozzle of

a f t e r the actuation pressure has been released.

expander tube, and remove O-rings (7) from

This brake system receives its oil supply

nozzle.

(OE/HDO10), from the forklift's main hydraulic

d. Cleaning, Inspection, Repair, and Re-

o i l supply tank. Pressure is provided by an en-

placement.

g i n e driven pump and application is controlled

( 1 ) Clean the brake assembly. Use a cloth

by an applicator valve. An accumulator is incor-

dampened in acetone or lacquer thinner. Do not

p o r a t e d in the brake system to provide operat-

s a t u r a t e components.

i n g pressure when the engine has stopped.

( 2 ) Inspect expander tube for signs of ex-

cessive heat shown by brittleness, or loose fab-

CAUTION

ric or rubber around the nozzle base that might

Check the lining, frequently, for wear. To

p e r m i t fluid leakage.

check wear, apply the brakes and look

( 3 ) Check for loose expander tube shields.

i n t o the spring openings in the brake

Recement all shields as described in (11) below.

frames. If the brakeshoe tends to shear

(4) Inspect brake block and shoe assemblies

the spring at a point between the frame

for separation of lining from shoe.

and the shoe (approximately 1/8 inch space

between top of spring opening and the

NOTE

l e d g e of the shoe upon which spring

The friction on the braking surface of the lining

rests), travel is at a maximum. Replace

may develop ridges and grooves. The leading edge,

the linings and springs before this condi-

that which is in the direction of rotation, tends to

tion is reached. Continued operation in

wear slightly unevenly. Either of these conditions

is normal.

t h i s condition will damage the brake

structure.

(5) Inspect the frame assemblies for un-

u s u a l wear or distortion of torque bars, cracks

b. Removal.

a t the welds of torque bars, and for cracks or

(1) Remove wheel (TM 10-3930-242-12).

e l o n g a t i o n of frame bolt holes. Frames should

(2) Refer to figure 5-4 (15 thru 60) and re-

not have more than 1/16 inch longation of the bolt

m o v e the brake assembly i n numerical sequ-

holes.

ence.

5-18