RACK-PISTON AND WORM ASSEMBLY AND GEAR HOUSING ASSEMBLY

install two screw and lock washer assemblies and

worm assembly for excessive lash or excessive load

tighten to 8 to 12 foot pounds.

overcenter and also for roughness at any point along the

(9) Insert rack-piston arbor tool into worm.

worm. If any of these conditions is found, disassemble

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

the assembly and inspect worm and rack-piston nut

separate from worm until rack-piston nut is fully on

grooves and all the balls for excessive wear or scoring.

arbor.

If either worm or rack-piston nut need replacing, both

must be replaced as a matched assembly. The lash or

6-167. RACK-PISTON AND WORM ASSEMBLY AND

heavy load may be corrected by replacing the standard

GEAR HOUSING INSTALLATION. Proceed as follows:

balls with a larger or smaller size. Black balls need not

(1) Assemble thrust bearing (80) and races

be replaced unless they are defective. In event the

(79) on worm (71). Assemble valve assembly to worm

black balls cannot be distinguished from the standard

by aligning small slot in valve body (87) with pin on

balls, replace with new balls.

NOTE

worm. Be sure to install packing (92) between body and

worm head.

The black balls are 0.0005 inch smaller than the

(2) Install valve assembly and worm in

silver balls. The black and silver balls must be

housing (97) as integral unit and continue valve

installed alternately into the rack-piston nut and

assembly as outlined in paragraph 6-166. Adjust thrust

return guide.

bearings.

(5) Inspect ball return guides (76), making

(3) Install piston ring compressor in gear

sure that the ends where the balls enter and leave the

housing (97). Hold it tight against shoulder in housing.

guides are not damaged.

Insert rack-piston ball nut (77) into housing until arbor

(6) Inspect lower thrust bearing (80) and

engages worm. Turn stub shaft (88) clockwise, drawing

races (79).

rack-piston nut into the housing. When piston ring is in

(7) Inspect rack-piston ball nut (77) teeth for

housing bore, withdraw arbor from rack-piston nut.

wear and chipping. Inspect rack-piston nut surface for

Remove ring compressor.

scoring or burrs.

(4) Install rack-piston plug as outlined in

paragraph 6-162.

6-166. RACK-PISTON AND WORM ASSEMBLY AND

(5) Install housing end plug as outlined in

GEAR HOUSING ASSEMBLY. Proceed as follows:

paragraph 6-160.

(1) Thoroughly clean the parts and lubricate

(6) Install sector gearshaft and side cover as

the internal parts with SAE 10 engine oil.

outlined in paragraph 6-159.

(2) Drive new connectors (95 and 96) in place

with piloted driver.

6-168. STEERING GEAR LASH ADJUSTMENT.

(3) Lubricate a new back-up packing (73) with

Proceed as follows:

SAE 10 engine oil. Assemble in piston ring groove on

(1) Disconnect the steering arm from the

rack-piston nut (77). Install new piston ring (72) in the

sector gearshaft and remove the horn button.

ring groove over the packing by carefully slipping ring

(2) Turn the steering wheel 1/2 turn off center

over the rack-piston nut. The ring may be slightly loose

(either direction). Using a 24 inch pound torque wrench

after assembly. This is normal. It will tighten when

on the steering wheel nut, determine the torque required

subjected to the hot oil in the system.

to rotate the shaft slowly through a 20 degree arc.

(4) Insert worm (71) into rack-piston nut, to

(3) Turn the gear back to center and

bearing shoulder.

repeating the method of reading torque as in step b.

(5) Align the ball return guide holes with the

above, loosen lash adjuster locknut (44), turn screw (47)

worm groove. Load 24 balls (78) into the guide hole

in until the reading is equal to six inch pounds in excess

nearest the piston ring, while slowly rotating the worm

of reading obtained in step b. above, and retighten the

(71) counterclockwise to feed the balls through the

locknut while holding the screw in place.

circuit. Alternate the black balls with the standard balls.

(4) Recheck the readings and replace

(6) Fill one of ball return guides with

steering arm and horn button.

remaining six balls. Place other guide over balls and

plug ends with automotive grease to prevent balls falling

6-169. THRUST BEARING ADJUSTMENT.

This

out when installing guide into rack-piston nut.

adjustment is to be made after the worm, thrust

(7) Insert guides into guide holes of rack-

bearings,

piston nut. Guides should fit loosely.

(8) Place return guide clamp over guides,

6-41