A while back, my car started having some weird steering issues. Basically, I'm driving straight it would track straight then feel like the steering would shift. I would have to move the wheel a little to continue going straight, then it would track straight again. Then it would shift again, etc. There is ZERO play in the steering wheel, and it never does this when turning. At highway speeds and above this starts to get quite scary as it seems genuinely unstable. My car is down for a rebuild right now so I can't do any road testing, but I need some ideas on what to check.

Could a bad wheel bearing cause this? Loose suspension bushings? It does have over 250k on the chassis. Any help is appreciated!

Edit: I did whack a curb about about 10 MPH but I think it was well before this started happening.

 

if the wheel comes back to random places, that kind of points to a bad steering rack bushing. when the bushings die, the rack can actually move side to side.

and since you're in there, look for loose wheel bearings, and tie rods

 

tie rods, ball joints, steering rack bushings (that hold the rack to the subframe). Wheel bearings can be checked when you check the tie rods, ball joints must be checked with front of car on ground and pulling on 6/12 o clock position.

 

What is so weird about it is that the steering wheel nevers moves, its just that I can tell that the car is starting to pull to one side so I have to correct with the steering wheel to keep it going straight and it only happens when there is zero lateral load. These "shifts" only happen every 10-15 seconds at most when at highway speed. Honestly, it feels like something is shifting in the rear. Is that possible? Anyway, I'll check out what I can when I get home. Its currently up on jack stands with no engine.

Keep the ideas coming!

 

DTSS bushing, laternal links in rear would cause to changes which result in steering change, even loose toe adjustment bolts. What you describe sounds like something from the rear.

 

The previous owner tracked it regularly and did a good bit of suspention work. I know he installed DTSS bushings, but I don't know about the rest of the suspention bushings. Either way, I'll still check them out since its probably been 75k miles of hard driving since any of that was done.

I know this is a stupid question, but what do I look for? Will the bushings be obviously torn, or just worn out looking, or what? I've rebuilt everything on the car but the suspension, so I'm still a bit new to it.

Thanks again

 

you will see broken bushings if they are bad enough. The best way to test suspension is just grab the swing arms and start shaking hard. Listen for any abnormal noises. Any movement while shaking will result in movement while driving, only worse. Check all the bolts to your struts and the toe adjustment bolt (make sure its tight). Check the dogbone for the subframe and the bolts that attacht the hubs to the swing arms. Check the lateral links (my guess is this is bad) and the small tiny links that connect the subframe to the swing arms.

Pull up the rear suspension diagram off the FSM and use that as a reference. Pay attention to all the bolts and components that are used to make the suspension connect toghether. Then look for those parts on your actual car and start checking for play and bent components. Any clunking or loosness on suspension = bad.

Don't forget to check the front end of the car also. At the end of the day, if all is snug, check alignment.

 

If the steering rack was moving slightly in the bushing, the steering wheel probably wouldn't move, would it?

 

Check the rear wheel bearings. If they are worn out the rear of the the car will move.

 

since it feels like something is loose, your best bet is to pull on the wheels, and see if something is loose

 

Take your car to a mechanic that does alignments and have them do a shakedown.

 

Does the car have power steering?

 

I checked the steering rack, and it appears solid. It has manual steering using a manual rack, not a modified power rack.
The front wheels appear to be solid, but I haven't been able to check out the rears yet. Because of the way I have the transmission supported I'm going to have to get creative to raise up the rear of the car. As for the wheel bearings, I actually think that at least one of my rear wheel bearings is bad. I definitely remember one of the wheels feeling like it was dragging some, but I never ruled out the brakes. As for taking it to an alignment shop; I would like to but it can't leave the garage right now. I'm tyring to diagnose the suspention stuff before I get the new engine in since it will be several months before I save enough to get it rebuilt.
Thanks again for the suggestions, and hopefully I can take a good look at the rear in the next few days.