THANK YOU DEL. THIS is what almost everybody is missing! THE STEERING BOX HAS A CENTER POINT AND
THIS IS WHAT SETS THE CENTER OF STEERING. Making the tie rod ends have equal exposed threading, or putting the 'center' exactly in the center of the steering travel are both incorrect and will result in steering 'slop' going straight.
Centering the straight-ahead, center adjustment of the whole steering system on the
steering box's center is important because the lash between the 2 gears in the steering box is at it's tightest at this 'steering box center point'. And that is important because, as you are cruising straight down the road, you want the box's gear lash to be snug and that will minimize play in the wheel.
I do the following to find this 'steering box center point':
- Jack up the front end
- Loosen the top nut on the box and tighten the adjustment screw CW no more than 1/4 turn. (This tightens the lash between the sector and worm gears.)
- Turn the wheel back and forth around the center area of steering, and see if you can feel a point where the steering is a bit tight. That peak tight spot is the center point of the steering box.
- If you cannot feel it, tighten the adjustment screw a bit more CW and repeat. Do this 'til you can juuuust feel that tightness in the steering box's center-of-steering. (There are actually procedures in the older FSM's to use a torque measuring device on the steering column to adjust that lash tightness at the center.)
- THAT is the center of steering. The steering wheel should be centered at that point. If it is not, then on the older cars, recenter the wheel there by pulling and re-installing the steering wheel. For the later ones, the master splines should be in the right place.
- Once that is done, only then are the tie rods are adjusted to make the car steer straight with the steering box and steering wheel at that TRUE center of steering position. The tie rods can be at different adjusted lengths when this is completed, and there may be some small difference in the number of turns between center and locked on each side. THAT IS OK, and reflects the tolerances in the parts of the steering gear and suspension.
- If the tie rod ends are waaay off from each other, then likely the pitman are needs to be adjusted on the box splines. But IIRC this is master splined too on the later boxes so cannot be too far off.
MANY (MOST?) ALIGNMENT GUYS NOWADAYS DO NOT KNOW OF THE EXISTENCE OF THIS 'STEERING BOX CENTER', so don't count on them to do it right. I had my local guy mess it all up after I set it up correctly and TOLD him to not mess with the relative lengths of the tie rods but adjust them equally in or out to set the toe-in. I'll be damned if he didn't equalize them and the steering box was then off center and the steering action was now loose..... geesh.