Car jerks over bumps
 

Hi all,

I notice that the front of my 87 300D tends to jerk left or right (steering wheel too) when I hit a bump in the road, like poorly maintained railroad tracks. Similar where the joint between bridge and road is poor. It also seems to hit harder than it should. Its been like this for a little while, it did not just appear one day.

There is nothing in the suspension that hasn't been replaced (age related issues, not directed at this!) - struts, shocks, subframe mounts, spring pads, springs, rear links, front lower contorl arms - all parts from dealer.

The front end steering is tight. Shaking wheels at 3 & 9, 6 & 12 shows no play. Steering damper is 48Kmi old (Feb'02). The wheels move evenly together, except when turned all the way - there is some free play, as if its coming from the steering gear itself.

Any ideas on what's causing this? Is it as simple as a new steering damper?

I also noticed that the passenge side spring touches the strut! When I turn the wheels side to side, there is a small amount of friction as the two rub past. I don't believe it was like this when I installed the spring two months ago (dealer spring, 22-04, with 3 lug pad per dealer). The spring is seated correctly as far as I can tell. In the lower control arm, I had to turn it 1/4" back from the stop elsewise it seemed the lower coil of the spring would not fit correctly in the control arm perch.. Don't know if its related.:confused:

My '86 300E had the exact same symptoms.

Read about what caused it HERE

Freestyler

Hello,

I JUST replace that support joint and other parts in the rear & my alignment will be Monday. Is it possible that incorrect toe-in is causing this behavior? If not I can hopefully repair what is over the long weekend.

Thanks,
Brian

Ive found out that toe-in could cause this behavior, so after the alignment Monday I'll know if my problem goes away.

Happy Holidays

Could indeed be alignment, but...

How much free play in the steering before the wheels start to turn?

With the car off (steering column unlocked), stand outside with window open, and see how far you can turn the steering wheel back and forth before the wheels react.

Problems here could cause the symptoms you describe. You have replaced every other suspect on the front end.

I have found that most high mileage 124s can benefit significantly from a steering box adjustment to take up play in the box.
This can really improve straight-line center feel, particularly over rough surfaces, and in the wind.

I have also read that the steering coupler on the steering shaft can cause excess play, but have not yet observed that particular problem.

Best of luck.

Hi csnow,

The steering has been adjusted before and show no unreasonable play. I turn the wheels, and the steering wheel turns except at the very left or right where there is a small amount of play. The front end feels good, I don't believe the car starts to jerk until the rear clears the pothole or railroad tracks.