Have a look at this current thread

http://www.peachparts.com/shopforum/diesel-discussion/365362-what-steering-problem-2.html

I replaced the ball joints. They were rusty, but didn't seem too bad... Anyway, the problem is still there. It is a bit less severe though, so the joints must have been somewhat tight. There isn't anything else in the front end except the idler arm, so I guess that's next.
I will update when that is done...
Thanks again for all the help

does your steering have dead free play in the center?

Have you checked the front toe in / out? A severe amount can make the car catch every groove in the road.

I use some 1" x 1" angle iron that is ~ 3 ft long and 6 bricks per side. Place the angle iron with a flat side against the tire ( above the bulge ), 2 bricks laid flat and stacked is a good height. Then place another brick on top of the 2 trapping the angle iron. Do this on the other side. Use a measuring tape at front and rear of the tire. If you don't have angle iron a yard stick will work.

If the front is smaller, you have toe in, if larger at front you have toe out. Something in the zero to 1/8" toe in range is typical for most cars.

So, what was the problem?

With a grease needle you can lube old ball joints if they are not loose.

I am surprised no one has mentioned caster since that is what brings the wheel back to center. I don't know how or if it is adjustable in that car though. Also tire pressure should be verified. Low tire pressure will do that.

Yes. Too little caster will make it not return properly and be unstable on the highway. Perhaps when the front end work was done it was misaligned.

This thread is five years old, but to answer the latest question camber and caster are adjusted on 124/201 models with the "cam bolts" that attach the control arms to the chassis. These cars are a "high caster" design, nominally about ten degrees. The front cam bolt primarily affects camber and the rear caster, but there is some interaction.

Since my '88 190E 2.6 is more front heavy (about 57 percent) than my former '84 190E 2.3 (about 53 percent) it exhibited more understeer, so I adjusted the front alignment for maximum negative camber and positive caster, equal on both sides, within the range of adjustment, which yielded negative 0.75 camber and 10.5 deg. caster.

I did the alignment myself in my garage using an inclinometer and string. Later I got the dealer to put it on the alignment rack at no charge, and their numbers were within .05 deg. of what I measured.

It's been that way ever since with no unusual tire wear, and understeer is much less than when new.

All that caster should yield good "steering feel" and very strong "returnability" of the steering wheel, but it has a downside... SHIMMY! That's why these cars have steering dampers. It's a high pressure gas (DeCarbon) type, and when it fails the car can go into a violent shimmy at about 55-60 MPH. I'm on my third one with only 85K total miles on the car, so it's as much about time as miles.

Fortunately the damper is relatively inexpensive and easy to swap out.

Duke

Have you tried a Bilstein damper?

I recently had a problem with steering not returning to center on my 107. Also occurred after a number of front end parts had been changed. Found that term for this was Memory Steer.

My cause turned out to be the new Lemfoerder idler kit I had installed. The steel sleeves that fit inside the rubber bushings were shorter than they should be. As a result, the assembly locked up when torqued to spec, causing the rubber bushings to turn in the chassis tube.

I at first corrected the problem by adding shim washers between the two metal bushings. But eventually returned the defective Lemfoerder part and installed an OE kit. Totally cured the problem.

My W201 had failing stiff ball joints and drove exactly like described above, very stiff, would not return to center. With new joints it was super smooth again.

Going to piggyback on this, can overtightening of the steering box cause excessive wander due to wind? My car is pretty good with exactly 0 wind, the slightest breeze and I'm all over the place. Had my indy drive my car this weekend and he said it feels like the box is overtightened and should return to center better than it does.

I've replace every steering and suspension component on the car in the last 9 months. Multilink rear, spring link in the rear, subframe bushings, new front LCAs, all new steering linkage, struts and springs. So in my mind theres really nothing left to replace other than the box.

It would help to include which model of car you have. Seems you don't have same problem as original poster in this thread - steering not returning to center. Sounds like you just have loose steering?

Have you checked the amount of steering slack you have at rim of steering wheel? On some models the maximum should be a total of about 1". This with engine off car stationary.

Adjustment of steering box is covered in shop manuals of some models.

W201

My indy is saying the return to center on my car is definitely lacking, I wasn't sure what was normal or inadequate there but he confirmed it should coming to center a lot better than it does. He said it feels like a box thats been overadjusted. He wasn't able to say if there's correlation between the wandering in the wind and the lack of centering, thats what I'm curious about.

Unfortunately the adjustment bolts is seized up, only way I can get to it is with a wrench from underneath and I just can't get it loose.

I have less than inch of freeplay in the steering wheel.