Rack Piston and Worm Shaft Replacement

DISASSEMBLY
1. Remove side cover and pitman shaft.
2. Remove housing end plug.





3. Remove rack piston plug.
4. Turn stub shaft COUNTERCLOCKWISE until the rack piston begins to come out of the housing.





5. Insert Arbor C-4175, or equivalent into bore of rack piston and hold tool tightly against worm shaft.
6. Turn the stub shaft COUNTERCLOCKWISE, this will force the rack piston onto the tool and hold the rack piston balls in place.
7. Remove the rack piston and tool together from housing.
8. Remove tool from rack piston.
9. Remove rack piston balls.





10. Remove clamp bolts, clamp and ball guide.





11. Remove teflon ring and O-ring from the rack piston.
12. Remove the adjuster lock nut and adjuster nut.
13. Pull the stub shaft with the spool valve and thrust support assembly out of the housing.





14. Remove the worm shaft from the housing.

ASSEMBLY

NOTE: Clean and dry all components and lubricate with power steering fluid.

1. Check for scores, nicks or burrs on the rack piston finished. Slight wear is normal on the worm gear surfaces.
2. Install O-ring and teflon ring on the rack piston.





3. Install worm shaft in the rack piston and align worm shaft spiral groove with rack piston ball guide hole.

CAUTION: The rack piston balls must be installed alternately into the rack piston and ball guide. This maintains worm shaft preload. There are 12 black balls and 12 silver (Chrome) balls. The black balls are smaller than the silver balls.

4. Lubricate and install rack piston balls through return guide hole while turning worm shaft COUNTERCLOCKWISE.





5. Install remaining balls in guide using grease to hold the balls in place.
6. Install the guide onto rack piston and install clamp and clamp bolts. Tighten bolts to 58 Nm (43 ft. lbs.).
7. Insert Arbor C-4175, or equivalent into bore of rack piston and hold tool tightly against worm shaft.
8. Turn the worm shaft COUNTERCLOCKWISE while pushing on the arbor. This will force the rack piston onto the arbor and hold the rack piston balls in place.
9. Install the races and thrust bearing on the worm shaft and install shaft in the housing.
10. Install the stub shaft with spool valve, thrust support assembly and adjuster nut in the housing.
11. Install the rack piston and arbor tool into the housing.
12. Hold arbor tightly against worm shaft and turn stub shaft CLOCKWISE until rack piston is seated on worm shaft.
13. Install pitman shaft and side cover in the housing.
14. Install rack piston plug and tighten to 150 Nm (111 ft. lbs.).
15. Install housing end plug.
16. Adjust worm shaft thrust bearing preload and over-center rotating torque.