Assembly Procedure

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Install the O-ring seal (3) and the teflon ring (2).
Lubricate both parts with power steering fluid.
Install the worm shaft (14) to the rack piston (4) outside of the steering gear housing (9).
Fully seat the worm shaft to the rack piston.

Fig 1: Assembling Steering Gear Housing
Courtesy of GENERAL MOTORS CORP.
Align the worm shaft spiral groove with the rack piston ball return guide hole (1).
Important: Improper rack piston ball installation may result in personal injury. The black rack piston balls are smaller than the silver rack piston balls. Install the black and the silver rack piston balls alternately into the rack piston and the ball guide to maintain the rack piston to the worm shaft preload.
Lubricate the rack piston balls with power steering fluid.
Insert the rack piston balls through the ball return guide hole (1) while turning worm shaft (2) counterclockwise in order to install the rack piston balls into the rack piston.

Fig 2: Aligning Worm Shaft Spiral Groove With Rack Piston Ball Return Guide Hole
Courtesy of GENERAL MOTORS CORP.
Install the remaining rack piston balls (3) into the ball guide (1) using grease at each end (2) to retain the rack piston balls (3).

Fig 3: Installing Rack Piston Balls Into Ball Guide
Courtesy of GENERAL MOTORS CORP.
Install the ball guide (3) to the rack piston (2).
Install the ball guide clamp (4).
NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
Install the screws (5).
Tighten

Tighten the screws (5) to 6 N.m (53 lb in).
Insert J 21552 into the bore of the rack piston while turning the worm shaft counterclockwise. The turning of the worm shaft forces the rack piston onto J 21552 . The rack piston balls remain in place.

Fig 4: Installing Ball Guide To Rack Piston
Courtesy of GENERAL MOTORS CORP.
Install the flat races (2, 4) and the thrust bearing (3) onto the worm shaft (1).

Fig 5: Installing Flat Races And Thrust Bearing Onto Worm Shaft
Courtesy of GENERAL MOTORS CORP.
Install the worm shaft (4) to the steering gear housing (3).
Important: Do not adjust the worm shaft until all components are installed onto the steering gear housing.
Install the spool valve. Refer to STEERING GEAR VALVE REPLACEMENT - OFF VEHICLE (700 GEAR) .
Install the rack piston (2) to the worm (4) from J 21552 using J 8947 to compress the seals.
Hold J 21552 tightly against the worm shaft (4).
Turn the stub shaft clockwise until the rack piston (2) is seated on the worm shaft (4).
Remove J 21552 from the rack piston (1).
Install the rack piston plug (1).
Tighten

Tighten the rack piston plug to 150 N.m (111 lb ft).
Install the housing end plug. Refer to STEERING GEAR HOUSING END PLUG REPLACEMENT - OFF VEHICLE .
Important: Do not adjust the pitman shaft until all components are installed onto the steering gear housing.
Install the pitman shaft seals and bearing. Refer to PITMAN SHAFT SEALS AND BEARING REPLACEMENT - OFF VEHICLE (670 GEAR) or PITMAN SHAFT SEALS AND BEARING REPLACEMENT - OFF VEHICLE (700 GEAR) .
To adjust the steering gear; refer to one of the following procedures:
- WORM THRUST BEARING PRELOAD ADJUSTMENT - OFF VEHICLE (700 GEAR)
- PITMAN SHAFT OVER-CENTER PRELOAD ADJUSTMENT - OFF VEHICLE (670 GEAR) or PITMAN SHAFT OVER-CENTER PRELOAD ADJUSTMENT - OFF VEHICLE (700 GEAR)
Fig 6: Installing Worm Shaft To Steering Gear Housing
Courtesy of GENERAL MOTORS CORP.