Firebird V8-305 5.0L (1982)
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.
Refitting Rack-Piston Balls
Do not refit balls unless the steering is loose. If such is the case, a thrust adjustment and over-center adjustment should correct the problem if it lies in
the steering gear. If balls are pitted or rough, then select the proper ball size for proper adjustment.
If the torque reading obtained above is too high or too low (on new balls only), disassemble and reassemble, using the next size smaller (or larger)
balls and recheck worm preload.
A rack-piston nut with a ball size of 7 does not have a number stamped on the flat surface. For ball sizes other than 7, the ball size is stamped on the
flat surface of the rack-piston nut. Ball sizes are numbered from 6 to 11, with 6 being the smallest and 11 the largest. Ball sizes are graduated in
increments of .00008 inch from .28117 inch to .28157 inch.
Disassemble
