Model 800-808 Steering Gear Assembly

Fig. 22 Checking worm preload:

The worm groove is ground with a high point in the center. When the rack-piston nut passes over this high point, a preload of a 1 to 4 inch pounds torque should be obtained.
1. With worm pointing up, clamp rack-piston nut in a vise with soft jaws (do not hold rack-piston nut in area of Teflon ring).
2. Place valve on worm, engaging worm drive pin.
3. Rotate worm until it extends 1-1/4 inch from rack-piston nut to thrust bearing face, Fig. 22. This is the center position.
4. Attach an inch pound torque wrench with socket on stub shaft, Fig. 22. Oscillate wrench through a total arc of approximately 60° in both directions several times and take a reading. The highest reading obtained with worm rotating should be between 1 and 4 inch pounds. Take a torque reading pulling the torque wrench to the right and a reading pulling the wrench to the left. Total both readings and take one-half of this total as the average torque. Do not use a torque wrench having maximum torque reading of more than 100 inch pounds.