The nut and screw adjust Worm bearing Preload and Sector shaft mesh. NOTE! The steering gear must be out of the vehicle to adjust it on all 1974 and later Saginaw rotary gear units. The earlier models can be adjusted (sector shaft preload) on vehicle.
This is how GM's Saginaw division recommends the adjustment be done.
- Disconnect the pitman arm from the sector shaft
- Completely back off the sector shaft adjusting screw on the sector shaft cover.
- Center steering on the "high point" then attach an inch lb torque wrench to the steering wheel shaft. The torque required to keep the shaft moving for one complete turn should be 1/2 - 2 in lbs. If the torque is not within these limits, loosen the thrust bearing locknut or tighten the valve sleeve adjuster plug to bring the preload within limits.
- Tighten the thrust bearing locknut and recheck preload.
- Slowly rotate the steering shaft several times then center the steering on high point.
- Turn the sector shaft adjusting screw until a steering shaft torque of 3-6in. lbs. more is required to move the worm through the center point.
- Tighten the sector shaft locknut to 35ft. lbs. and recheck the sector mesh adjustment. Total steering gear preload should be 14in. lbs. or less.
- Install the pitman arm and place the unit back into vehicle.
WARNING - To try and adjust the sector shaft screw without doing the preceding WILL DAMAGE the steering gear. Most of the play is not in the sector shaft adjustment, it is in the spool valve area.
