Odd suspension (?) problem -- W124

[McLoffs]

I'm having some suspension issues (or at least I assume it's the suspension) with my 1993 300E with 115,000 miles. Basically, it's not happy at high speeds. Keeping it in a straight line takes entirely too much effort, and it just feels loose. Also, periodically there's a slight shimmy/vibration at the steering wheel. The car also sometimes rides very roughly over freeway expansion joints (my Miata with Konis and low-profile tires rides better over them).

In the past six months, the car has new Bilstein shocks, a new steering dampener, and new thrust arms. I was hoping these would solve the problem, but no luck.

I know I'm due for a new belt tensioner shock, and the tires need to be replaced this summer. Don't know if either of those would affect anything, but thought I'd throw that out.

Any ideas what my next step is? I appreciate your help.

Thanks,
Mike McLaughlin

[BAd124]

Just an idea but you didnt mention anything about ball joints. These can cure alot of the loseness described in the system. Also the vibration mentioned could be due to the tires that need replacing due to deterioration or simply just out of balance. Also if the car has had severe shocks such as potholes you may want to check out the bushings in the front and rear suspension pieces as well. I know that if the rear ones wear out the geometry will affect the handling of the car. You may want to do this befor you get any new tires because if anything is out of line, you will just harm the tires. Just a few thoughts..:p

I have a similar problem as you McLoffs. My tires are new, my brakes were just replaced. I am pretty sure that I and perhaps you can rule that out. I was thinking steering dampener but I am not sure I have one. Just had the steering tie rod replaced, so for what it's worth I am leaning towards BAd124's suggestion of bushings or a particular ball joint or two...I am going to have it looked at, It is an uncomfortable feeling and somewhat instable like I could be pegged as a drunk driver or something, and I have excellent manual dexterity so it's got to be the car...

[McLoffs]

I'm going to sound like a dumb guy here (might as well be consistent, I suppose) but how do you check ball joints and bushings to see whether they need to be replaced? Sounds like an excellent excuse to get dirty working on the car this weekend.

It's also good to know there are others with similar problems, and that I'm not imagining things. :-)

[csnow]

The 'wandering at speed' problem is often balljoints.
Knocking or groaning noises when going over bumps at low speed also points towards balljoints.
Shimmy alone is often play in the rack (if not wheel balance, tire problems, etc.), such as idler arm bushings, any of the many tie-rods.

Here is how you check balljoints:
1) Place jack under control arm (as near to balljoint as possible) on suspect side, and lift until tire is about 3 inches off ground.
2) Make sure jack is really secure!
3) Grasp tire at 12 and 6 o'clock, and attempt to rock inwards and outwards. If there is any play, have an assistant observe the balljoint to verify the source (could also be the bearing).

Now check for play in the rack:
1) Grasp tire at 9 and 3 o'clock, then rock left and right.
2) Should be no play.

I have observed that the balljoint on the right side seems to fail first, and the idler arm bushings (also on the right) are short-lived, so suggest starting on the right.

[McLoffs]

Thanks for the information. I'll follow your instructions and hopefully figure out what's going on. And then hopefully figure out how to replace anything that needs replacement.

[CJ]

Check the ball joints for excessive play. the joints should have a substantial amount of pre-load on them.