Figure 5-8. Automatic slack adjuster, disassembly and reassembly.

TM 10-3930-242-34

Figure 5-8. Automatic slack adjuster, disassembly and

reassembly.

(18) Install the pilot valve adjusting plug

( 8 ) Place the spring (20) on the ball guide

(32) on which a new O-ring (33) has been instal-

(21) and then the washer (19), seal (18) (with lip

led.

t o w a r d the steel washer) and the teflon backup

ring (17).

(19) Screw the plug (32) down to the dimen-

(9) Place a new O-ring (16) on the plug (14)

s i o n , which was recorded at the time of disas-

a n d place the assembled parts inside the plug

sembly, and line up the slot in the plug with the

a n d assemble to the body.

mark on the face of the valve body (3). If new

(10) Tighten the plug (15) to 35-40 ft-lbs.

parts have been used to service the valve at this

(11) Place a new O-ring (30) on the pilot valve

point, there is a possibility that the accumulator

seat (29) and install in the valve body (3).

c h a r g i n g limits have changed. This is checked

(12) Push the pilot valve seat into place with

when the brake valve is installed on the vehicle.

a wooden dowel.

O n e full turn of the adjusting plug changes the

(13) Install the pilot valve spool (28), the long

high limit by 200 psi. The high limit is raised by

end of the spool in the "up" position.

screwing the plug into the body and lowered by

screwing the plug out of the body.

(14) Place the steel ball ( inch diameter) on

i t s seat in the pilot valve insert.

(20) Install a new quad ring seal (42) on the

(15) Install a new O-ring (25) on the plug (15).

charging valve spool (43) and install the spool in

Place a small amount of grease on the end of the

the body. Use extra care in installing this spool

spring (26) and insert it into the plug. The

so as not to damage the lands on either the spool

g r e a s e is to hold the spring in the plug during

or the body. Be sure that the spool is pushed all

assembly.

the way into the body so that the end of the

(16) Tighten the plug (15) to 30-35 ft-lbs.

spool contracts the plug in the end of the valve.

(17) Install the spring (34), ball seat (35), and

At no time is it necessary to force this spool.

s t e e l ball (36) ( in. diameter) using grease to

(21) Install the charging valve spring (40).

hold the ball and seat to the spring.

(22) Install the stop (41) inside the spring.

(23) Install a new O-ring (39) on the charging

valve plug (38), and insert it into the valve body.

CAUTION

I n s t a l l retainer ring (37).

Be sure that the steel ball is on the seat

(24) Install a new "V" block seal (14) on the

before proceeding further.

5-22