129-Shock Mount Questions-Knock when turning

[SunGuy]

'99 SL500, 53,000mi.

A knocking sound has developed recently when, for instance, backing out of a parking space and turning the wheel left or right. Same knocking sound is present also going forward...left or right turns. It's definitely coming from the front of the car, but I don't 'feel' it in the steering wheel. The under car steering elements appear to be tight with no evident slop in tie rods, center link, etc. and no fluid leak from the struts.

When checking the upper strut mounts while the car was standing still, I noticed they move, or rock, but I can't duplicate the knocking sound as when the car is moving; then I can duplicate it at will.

First question,
o are the upper mounts supposed to 'rock' as the wheels turn?

o if the answer to the above is either yes or no, is there an adjustment available to put the mount back in spec, and of course, what's the spec?

Thanks in advance for your help.

Bob

[jjrodger]

I am afraid that I cannot offer help but can confirm that I have had the same problem and it appeared to be an easy fix. I had exactly the same symptoms on a W124 300D way back in about 1992. I was on holiday in France at the time and took it into the local dealer on a Saturday morning. Their mechanic drove the car, heard the sound, took it round the back and returned it about half an hour later, fixed. I have no idea what he did to it. There was no charge. So perhaps there is some hope here!

[SunGuy]

jjrodger,

Thanks for your note; I hope it's something simple too! If nothing else, it's a great excuse for a trip to France!

Bob

[stats007]

I would say it's the steering damper - which if I'm right is a cheap and easy fix.

[SunGuy]

stats007,
Thanks for your comment...great minds work alike! When under the car the other day, I did notice what I believed was too much front to back flex in the steering damper, which I believe shouldn't move at all in that direction. I ordered one, it arrived yesterday and I'll install over the weekend. We'll see.

I'm still puzzled by the way the strut towers seem to flex or move when I turn the steering wheel. There are 3 bolts per side that I'll re-tourque this afternoon, but I'd really like to know the principle behind the way this mount works.

Bob

[SunGuy]

The knocking sound that I noticed when turning either left or right in my 129 turned out to be both the steering damper(shock) and strut mounts were bad. Steering is now back the way it should be. Thanks for the ideas!

Bob

[SL600 V12]

Yes indeed. Both are wearable components and should always be suspect in such a situation.