Original front shocks at 150k miles??
 

My '86 300SDL has about 150k miles (242500km) and I'm having a front suspension problem..

Sometimes when I hit a bump on the highway (anywhere from 60-80mph), the front left wheel begins "bouncing". I have to hit the brakes hard to slow the car down before the bouncing stops. The steering wheel shakes violently left and right until I slow down.

I think the vibration of hitting a bump is setting off some kind of harmonic vibration in the front suspension -- exactly the kind of thin (I think) a shock is supposed to dampen.

I looked at the front shocks yesterday. Can't see if there is any oil leaking on the silver "piston" rod because it has a cover over it. The outer housing of the shock looks dry.

My question -- Is the problem front shocks? The shocks do NOT look like the Bilsteins I bought for my other car (black with a coloured stripe on them). These are blue and have a white arrow pointing up that says "TOP". That is the only marking I can find on the shock.

The blue & white shock screams original equipment to me... am I wrong? The PO gave me a huge stack of receipts from the day he bought the car until now, and there is nothing about shocks ever being replaced..

Thanks for any help anyone could provide!

Neal

Neal,

Yes, the problem is front shocks. Replacing them is very easy and is a DIY project. I recommend Bilsteins.

If you have a shaking steering wheel, it indicates that the wheels need to be balanced.

Herb
'82 240D
'87 300SDL

Based upon the symptom you describe, it's shock-time.

I suggest Bilstein HDs, but their Comforts are fine as are OE

Is the handling in corners improved with the HD's over the Comforts?

HDs will improve cornering and high speed stability, but will give a more "busy" ride, as they react very quickly to surface imperfections...when you hit a bump, the event is over quickly, whereas with a comfort-oriented shock the event is longer.

Does that help??

Having to hit the breaks hard to slow the car down to stop the bouncing to me sounds like too much of a severe problem than just worn out shocks.

I would get your entire front suspension checked out to see if something isn't broken, become disconnected, etc.

Also, worn out tie rod ends can also cause relatively bad tire wobble. It feels like your tire is simply out of balance, but in reality, with a worn out tie rod end, you tire will wobble from left to right instead of bouncing up and down.

My 87 300TD developed a significant vibration that required braking or quick left right action to calm it down. The car had 185K and I was planning on changing the front suspension anyway. After taking it apart, no excessive wear or tell tale bushings worn, but the steering dampner was completely shot and leaking. Was not sure if it was caused by the vibration or was responsible. Left the shocks in since I had changed them 50k ago. Forgot to change the shock tower mounts and I wish I had. Everything is back to normal. Replace your steering dampner and see if it helps. An easy 1hr job and they are cheep.
Henry

I agree with Paul (2 notes above). This is a potentially very dangerous situation and if I were you I would waste NO time in getting the car into the hands of a competent tech to look over the front end.

This happened to me in the SDL ~6 months ago after HAMMERING over a LARGE pothole. A quick tap of the brakes remedied the situation. After explaining in detail to my competent mechanic, he stated quite matter-of-factly, "balance the tires". The problem has not returned.