Hydraulic Brake Valve (cont). - TM-10-3930-638-24-P0345

TM 10-3930-638-24&P

2-43. SERVICE BRAKE MAINTENANCE (cont)

c. Hydraulic Brake Valve (cont).

(2) Power Assist Unit (cont).

REMARKS

ITEM

ACTION

STEP

LOCATION

REASSEMBLY/REPAIR (cont)

Install

In groove of spool cap bore, with lips of

d. U-cup seal (27)

(cont)

and O-ring (26)

seal (27) facing open end of bore

e. Spool (9)

Position and

In soft-jawed vise, with narrow end of

clamp

spool facing up

f. Spring (25)

Install

Slide over narrow end of spool (9)

CAUTION

Exercise care when installing spool cap (11) so as not to damage

U-cup seal (27).

Install

Push wide end of spool cap (11) down over

g. Spool cap (11)

spool (9) and against pressure of spring

(25)

h. Retaining ring (24)

Install

Push into groove at end of spool cap, and

close with pliers until ring is tight in groove

Gland (2)

a. O-ring (21)

Install

In U-cup seal (22)

b. Gland (2)

Lubricate

Lightly coat bore with hydraulic oil

c. Backup ring (23)

Push against flat side of seal (22) in gland

Install

bore

d. U-cup seal (22) and

Install

In groove of gland bore, with lips of seal

O-ring (21)

(22) toward inner face of gland

e. O-ring (20)

Install

In groove at outside diameter of gland (2)

Power assist

a. Body (5)

Position and

In vise, with gland end facing down

unit

clamp

b. Poppet (19)

Lubricate

Lightly coat with hydraulic oil

CAUTION

Exercise care so as not to scratch or damage poppet (19) during

installation.

c. Poppet (19)

Install

In relief valve bore of body (5), with narrow

end of poppet facing up. Be sure poppet

goes all the way down to the seat

NOTE

Spring (17) and shim(s) (18) are matched for proper relief pres-

sure. Reassemble power assist unit using origrinal spring and

shim(s) only.

2-307