Section X. Hydraulic Brake System

condition is reached. Continued operation in this

3-48. General

condition will damage brake structure..

This section contains information on the main-

b. R e m o v a l .

tenance of the hydraulic brake system. This in-

(1) Remove wheel (TM 10-3930-243-12).

cludes the hand brake assembly, the hydraulic

(2) Refer to figure 3-106 (1 thru 40) and

brake system, hydraulic pump, brake valve, ad-

remove the brake assembly in numerical sequence.

juster, accumulator, and the hydraulic oil tank.

c. Disassembly. Refer to figure 3-108 and

3-49. Hand Brake Assembly

disassemble the brake assembly as follows:

a. General. The parking brake assembly is

(1)

Hold

the

brake

either

vertically

mounted to the transmission and connected to a

horizontally so that both frames (8 and 9) are

c o n t r o l lever handle on the right hand side of the

exposed.

driver's seat (TM 10-3930-243-12).

( 2 ) Place a screwdriver against the hook of the

b . Removal. Refer to figure 3-96, step 6 through

retracting spring (7) and with a sharp blow,

step 9, and remove the parking brake assembly.

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

c. Inspection.

through the brake and out of the assembly.

( 1 ) Inspect the brake shoe for excessive wear:

( 3 ) Lift the block and shoe assembly (5) from

( 2 ) Inspect all hardware for breaks or damage.

the frame.

(3) Replace a defective part.

(4) Remove brake frame bolts (2).

d. Installation.

( 5 ) Use center punch to mark upper and lower

( 1 ) Refer to figure 3-97, steps 52 thru 54, and

frames for same location on reassembly and lift

install parking brake assembly.

upper half of frame from torque plate (11).

(2) Adjust parking brake (TM 10-3930-243-

(6) Slide expander tube (12) and inlet con-

12).

nection (10) from the torque plate.

3-50. Hydraulic Brake System

NOTE

a. General. The brake assembly on the rough

If expander tube is stuck to the torque plate, work a

thin piece of steel between the torque plate and ex-

terrain forklift is the expander tube brake, 360

pander tube and draw it around the plate to free tube.

segmented, shoe type actuated by an expander

tube. Its components include a cast torque plate

(7) Remove inlet connection from nozzle of

upon which the expander tube is mounted and an

e x p a n d e r tube, and remove O-rings (3 and 4) from

inlet connection into which the nozzle of the ex-

nozzle.

Inspection, Repair, and

pander tube is inserted. Steel side frames with

d. Cleaning,

w e l d e d steel torque bars are attached to both sides

Replacement.

o f the torque plate. Brake linings mounted on steel

(1) Clean the brake assembly.

s h o e s are inserted between the torque bars and side

(2) Inspect expander tube for signs of ex-

frames and held in position by retracting springs.

c e s s i v e heat shown by brittleness, or loose fabric or

Steel shields are used to bridge the gap between

rubber around the nozzle base that might permit

shoes and protect the expander tube. The spring

fluid leakage.

inserted under the center of the linings and over

(3) Check for loose expander tube shields.

t h e steel brakeshoes withdraw the block, and shoe

R e c e m e n t all shields (6) as described in (11) below.

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

(4) Inspect brake block and shoe assemblies

the actuation pressure has been released. This

f o r separation of lining from shoe.

b r a k e system receives its oil supply (OE 10), from

NOTE

the forklift's main hydraulic oil supply tank.

The friction or braking surface of the lining may

P r e s s u r e is provided by an engine driven pump and

develop ridges and grooves, The leading edge, that

a p p l i c a t i o n is controlled by an applicator valve. An

which is in the direction of rotation, tends to wear

slightly unevenly. E i t h e r of these conditions is

a c c u m u l a t o r is incorporated in the braise system to

normal.

p r o v i d e operating pressure although the engine has

stopped. Check lining frequently for wear. To

( 5 ) Inspect frame assemblies for unusual wear

c h e c k wear, apply brakes and look into the spring

o r distortion of torque bars, cracks at the welds of

openings in the brake frames. If the brakeshoe

t o r q u e bars, and for cracks or elongation of frame

tends to shear the spring at a point between the

bolt holes. Frames should not have more than

frame and shoe (approximately 1/8 inch space

1/16 inch longation of the bolt holes.

b e t w e e n top of spring opening and the ledge of the

(6) Check for broken or distorted retracting

shoe upon which spring rests), travel is at a

springs, comparing questionable springs with new

maximum. Replace linings and springs before this

ones.

3-155