HOUSING INSTALLATION.

TM 10-3930-623-34

4. Insert worm (59), without thrust bearing, fully

inch-pound torque wrench and 12 point 3/4 inch socket

into rack-piston ball nut (65).

on lower shaft (76).

5. Align ball return guide holes with the worm

2. Tighten adjuster plug to add preload of 1 to 3

groove. Load all except seven balls (66) lubricated with

inch-pounds in excess of valve assembly drag. Tighten

OE-10 engine oil into the lower guide hole nearest the

locknut (49). Total thrust bearing adjustment and seal

piston ring, while slowly rotating the worm (71)

drag is not to exceed 8 inch-pounds.

counterclockwise to feed the balls through the circuit.

Alternate black balls with silver balls.

6-92. LASH ADJUSTMENT. This adjustment is to be

6. Fill one of ball ret urn guides (64) with remaining

made after the gear is completely assembled.

seven balls. Place other guide over balls and plug ends

with automotive grease to prevent balls falling out when

1. Back off lash adjuster screw (33, figure 4-32)

installing guide into rack-piston nut.

fully.

7. Insert guides (64) into guide holes of rack-piston

2. Using an inch-pound torque wrench and 12 point

nut. Guides should fit loosely.

3/4 inch socket on the stub shaft (76), rotate fully

8. Place return guide clamp (62) over guides,

counting turn between each end. Turn to center position

install two screw and lock washer assemblies and

which is half the total turns from one end.

tighten to 8 to 12 foot-pounds.

3. Rotate stub shaft through a 20 deg. arc noting

9. Insert rack-piston arbor tool into worm. Turn

torque reading. Verify with several readings.

rack-piston onto the arbor. Do not allow arbor to

4. Tighten lash adjuster screw (33) until torque

separate from worm until rack-piston nut is fully on arbor.

wrench reading is 4 to 8 inch-pounds higher than that

obtained in step 3. Reading should not exceed 14 inch-

pounds.

6-90. RACK-PISTON, WORM ASSEMBLY AND GEAR

5. Using a crowfoot adapter and foot-pound torque

HOUSING INSTALLATION.

wrench, tighten locknut (34) to 25 foot-pounds while

holding the adjuster screw with a hex socket wrench.

NOTE

Lubricate all parts during assembly

with OE-10 engine oil.

6-93. MASTER CYLINDER ASSEMBLY.

1. Assemble thrust bearing (68, figure 4-32) and

6-94. ASSEMBLY.

races (67) on worm (59). Assemble valve assembly to

worm by aligning small slot in valve body (75) with pin on

NOTE

worm. Be sure to install packing (80) between body and

Wet master cylinder interior parts

worm head.

with hydraulic brake fluid, Fed Spec

2. Install valve assembly and worm in housing (87)

FV-H-910 during assembly.

as integral unit. Adjust thrust bearings as outlined in

paragraph 6-91.

1. Assemble in brake master cylinder in order the

3. Position ring compressor (see figure 6-13 for

following: check valve (40, figure 4-10), spring (39), cup

tool details) in gear housing (87) tight against shoulder of

(38), piston assembly (37), stop plate (36) and retaining

housing. Insert rack-piston ball nut (65) into housing

ring (35).

until arbor engages worm.

Turn stub shaft (76)

2. Assemble clevis end (24) and locknut (25) to

clockwise, drawing rack-piston nut into housing. When

push rod (33). Adjust clevis distance between the eye

piston ring is in housing bore, withdraw arbor from rack-

center and the outer end of the push rod hex to 2-3/8

piston nut. Remove ring compressor.

inches. Hold push rod and tighten locknut. Assemble

4. Install rack-piston plug as outlined in paragraph

boot (34) and push rod to master cylinder.

6-85.

3. Assemble gasket (30), brake line swivel fitting

5. Install housing end plug as outlined in paragraph

(29), gasket (28) and hollow swivel bolt (27) to master

6-83.

cylinder.

6. Install sector gearshaft and side cover as

outlined in paragraph 6-81.

NOTE

Fitting is installed with 1/8 NPT port

THRUST BEARING ADJUSTMENT.

This

6-91.

at top and the 1/4 inch OD tubing port

adjustment is to be made after the worm, thrust

to center of truck.

bearings, valve assembly, adjuster plug assembly, and

locknut are assembled in the housing assembly Proceed

4. Assemble reservoir cap (31) and gasket to

as follows:

master cylinder.

5. Assemble stop light switch to swivel fitting.

1. Tighten adjuster plug (52, figure 4-32) up snug,

back off 1/8 turn and measure valve assembly drag with

6-23