Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Rack-Piston Nut & Worm: Installation
Install thrust bearing and races on worm, then assemble valve to worm by aligning small slot in valve body with pin on worm (be sure to install "O" ring seal between body and worm head). Install valve assembly and worm in housing as an integral unit and install valve (see "Rotary Valve" above). Install Rack-Piston Seal Compressor, J-7576, in gear housing, holding it tightly against shoulder in housing. Insert rack-piston nut into housing until arbor engages the worm, then turn stub shaft clockwise, drawing rack-piston into housing. When piston ring is into housing piston bore, remove Tool J-7539 and J-7576. Lubricate new "O" ring seal with transmission oil and install on rack-piston end plug (do not allow "O" ring seal to twist in groove). Install rack-piston end plug, tapping it into place with a mallet. Install retaining ring with snap ring pliers and make sure it is bottomed in groove. Lubricate new housing end plug "O" ring seal with transmission oil and install in gear housing. Insert end plug into housing and seat it against "O" ring seal, tapping it into place if necessary. Snap end plug retainer ring into place with fingers and bottom it securely in gear housing. Install pitman shaft assembly (see above).
| Ball Size | Range |
|---|---|
| 6 | 28112-.28122" |
| 7 | 28120-.28130" |
| 8 | 28128-.28138" |
| 9 | 28136-.28146" |
| 10 | 28144-.28154" |
| 11 | 28152-.28162" |
| Car Model | Preload (Inch Lbs.) |
|---|---|
| American Motors | 1-4 1/2 |
| Buick | 1-5 |
| Cadillac | 1-4 |
| Chevrolet | 3 |
| Ford | 1-4 |
| Jeep | 1-4 |
| Oldsmobile | 1-4 |
| Pontiac | 1-4 |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.