94 f150 4x4 302 5l E4od trans

So my rebuild project is moving along.
I completely rebuilt the front end of the truck:
ball joints upper and lower both sides.
axle u joints all
Axle pivot bushings
tie rod ends (not the tie rod at the pitman arm I'm swapping the box and will address this once I pull the column etc)
360 degree camber bushings installed
truck properly aligned by a shop that actually knew what they were doing
castor camber and toe all bang on I watched him do it.
The diff was stripped, cleaned, sealed etc
new coils
new shocks (quad shock setup)
New control arm bushings AND mounting brackets.
new bearings and races innmer and outer.
new spindle bearings etc

So the problem Im having is at slow speeds the truck stays dead straight. As I increase speed and make any minor steering movements the truck will stay stuck on that path sometimes until I correct it back straight. At which point if I overcorrect and center the wheel the truck will stay stuck in that direction.

I have to constantly make corrections and overcorrecting frequently. It feels like the steering wheel has the usual play looseness of an old Ford lol. But like the knuckles once turned, stay stuck in that direction until corrected.

its very odd.

ive heard the U joints in the steering column can cause this. Im wondering if its that or maybe the tie rod at the pitman arm maybe? I did adjust the gear box screw as well to tighten up some of the slack but it did nothing with the binding steering issue.

What can cause this?

 

Hello. just to get it right; your steering NEVER goes back to the 0 position by itself? So if it has been measured, it can only be because one or more joints or the steering gear are extremely stiff.

 

The tension screw on top of the box is not to reduce slack. It is the preload on the bearings. The only time I have seen symptoms such as you describe is when that screw was too tight. I would back it off a whole bunch and see what happens.

 

Huh...
I will give it a try.

Its hard to explain. Picture driving and you make a turn and straighten the wheel but the truck is stuck going off to the side wandering slighly left lets say.

You have to bump the wheel right (past center because of the standard slack in the steering wheel in these old beasts) to get it back straight again.
center the wheel.
If you overdid the correction the truck will now stay wandering to the right. Then have to bump the wheel back left again to try and get the wheels pointing straight.
So on so forth.

 

As mentioned that screw is set to preload the assembly. I have used it to take some of the on center slop out of the box to extend its life but you do that in very small increments. If too tight if can cause binding and ruin the steering gear.

When I got my truck the ball joints were so stiff that it would not allow the wheels to return to center but you stated that both sets (upper and lower) had been replaced.