Hydraulic Brake Valve (cont). - TM-10-3930-638-24-P0342

TM 10-3930-638-24&P

2-43. SERVICE BRAKE MAINTENANCE (cont)

c. Hydraulic Brake Valve (cont).

(2) Power Assist Unit (cont).

REMARKS

ACTION

ITEM

LOCATION

STEP

REMOVAL

From gland (2)

Front chassis,

a. Rubber cover (1)

Grasp and pull

Loosen and remove Support body (5)

b. Four cap screws (3)

bottom left side

and lock washers (4)

Remove

Pull straight from bracket until clear of

c. Power assist unit

push rod (7); then lower and remove from

body (5)

vehicle

Remove and

From push rod (7)

d. Rubber cover (1)

discard

DISASSEMBLY

Position and clamp In vise, with gland (2) facing upward

Power assist unit

a. Body (5)

WARNING

Exercise care when removing gland (2). There will be spring ten-

sion against the gland. Failure to do so may cause gland to fly

into your eyes.

b. Gland (2)

Loosen and remove Turn counterclockwise using spanner

wrench or chain wrench and pull from

body (5)

Remove

Pull from body (5)

c. Spool (9), piston

(10) and spool cap

(11)

Remove

From spool (9)

d. Piston (10)

e. Piston ring (12)

Remove and

Use piston ring pliers

discard

f. Spring retainer(13)

Remove

Pull from body (5)

and spring (14)

g. Body (5)

Reposition and

In vise, with gland end facing down

clamp

h. End plug(15)

Remove

From body (5)

i. O-ring ( 16)

Remove and

discard

j. Spring (17), shim(s)

Remove

From body (5)

(18) and poppet (19)

NOTE

Spring (17) and shim(s) (18) are matched set. Retain shim(s) for

reassembly with original spring (17).

From gland (2)

a. O-ring (20)

Remove and

Gland (2)

discard

From bore in gland (2)

b. O-ring (21), U-cup

Remove and

discard

seal (22) and backup

ring (23)

2-304