If your steering when doesn't return to center
 

Consider changing your lower ball joint! Especially for the models that only have the lower ball joint/wishbone set up like the w201s.

That is the dumbest thing i have heard lately. the ball joint does not make the steering return to center the caster adjustment of the aliegnment does that. maybe yours was stiff and could not turn without the force of the pump but it does not make the steering turn back straight

Uhhh yeah lots of times when you have worn out and poorly lubricated ball joints it will cause the steering wheel to "stick" where ever you put it. This isn't limited to mercs either, pretty common. I have a car exhibiting this behavior right now due to worn ball joints...

worn ball joints will have all the play needed to move around more than they should.
dry or lacking in lube can make it hard to move
a general inspection with every oil change will spot those problems before there is any lack of movement

and to tell everyone to just change them without looking to find if that is your problem is a waste of money

Post edited to "consider changing" your ball joint. My car is fixed and the steering now returns back to center as it should.

New ball joints are great! Fairly easy to change on a w201/w124 style control arm. Arms in place. No spring compressor. Just need the right kind of ball joint installation tool.

Just did mine. Super smooooooth!

A few years back people were reporting sticking steering dampers were messing up their steering too

So - sure - there's a correlation of the condition of parts with your driving experience!

a bad ball joint on a W124 will cause the camber and caster to out of spec. In certain conditions you may feel the car wants to scrub while doing sharp turns. In that condition your car wont want to steer back from sharp turns. Mild turns will be okay though.

replaced my balljoints,lower control arm bushings,and steering wheel is off.However no bad tire wear.

if the ball joint has enough play to change caster or camber it will probably shake the steering wheel and would be easy to find on your oil change inspection. its not just the worn ball joint its telling people to just change them if the steering wont return straight. op has edited the original post to reflect that fact

if a quick inspection is done with every oil change this would be caught before it got to the point of not returning to center. thats the reson why shops charge more than most people want to pay for oil change because they are doing more than just changing the oil and filter

when i drive down the road and see someones steering wheel shaking or a tire bouncing around i will change my speed to get away from that neglectful person. they dont make the cars i drive anymore and i dont want anything to happen to them

The way my ball joint failed is that it completely separated. It was a process as the ball portion slowly began to come out of the socket. When that happens the ball joint is actually stiff so there will be no play. When my steering wasn't returning to center I checked my front components and found nothing out of the ordinary. The only other symptom was that when I was braking the car would pull towards the passenger side (the failed side). So I originally thought a stuck caliper, but that didn't make sense as to why the steering was not centering after a turn. Also, the ball joint never exhibited any of the typical warning signs like the loud groaning and popping while making a slow turn. Yes, I did edit my post because I made a mistake by assuming that anytime steering is not returning to center has to be the ball joint, just like you are making the mistake by assuming that all ball joints will fail in the same manner: by having play, shaking steering wheel while driving, etc. I had none of those symptoms that you mentioned and aside from the not returning to center, my car never wandered to either side while driving.