Strange Thumping Noise 1979 230

[sanclaro]

Hi, Hope someone can help. I've just bought my first classic Mercedes. It came with a full years MOT (undertaken at a reputable garage). I noticed on the advisory slip that they had recorded a noise coming from the rear suspension when roadtested, but none of the suspension components failed its MOT. Sure enough it is there when you go over bumps, sounds like the noise an exhaust would make if it were loose and bashing against the suspension mounts etc. I've looked thoroughly over it and cannot see what is causing it. I would be enormously grateful for any suggestions as to what is causing it.

Thanks

Andy

 

[Aussie Nick]

No one apart from yourself ,will find the cause here. Suggest you lift her up and examine from underneath what may be the probable cause . On what you have described the cause should be apparent and less than cryptic.

 

[Dec]

Clear everything out of the boot, particularly any carpet/flooring, place a small schoolboy in the boot with the promise of financial reward if he can find the location of the noise, this may narrow your search, as to which area of the car to inspect more closely.

Dec

 

[Aussie Nick]

Dec I think one of the Little people would be more appropriate than the schoolboy.

 

[Dec]

I new you would say that! The only accept payment in gold, the are a bit deaf anyway due to there age.

Dec

 

[wireman]

My current (124) hobby horse is the front mountings on the rear sub frame, I am not sure that the 123 has the same setup.
However a friend turned up with a clonking 124.
I could not find any source for this despite looking and levering in all the suspect places you just cant get enough force up to move the frame against the weight of the car.

So I did a bit of a dangerman test, this is how:-

Park the car with one wheel on the kerb, this makes more space for you to lie beneath it.

Apply the hand brake firmly, leave it on for the rest of this check.

Start it and get an assistant to inch/rock the car back and forth against the handbrake.

Tell the assistant that you will kill him/her if the hand brake is released, the exercise is only intended to rock the car a little.

Lie under the car and watch the rear suspension bits for movement as torque is applied in both forward and reverse gears. There are some 30 rubber bits on the 124 rear so find and identify them and a good position to observe them in action before you start shifting the car fore and aft.

The bit that winds up or moves is probably on the tired and sorry side of being useable.

In the case of my mates car it was the front mount on the LH side and the car has now gone to the great motorway in the sky due to the silly pricing of the repairs.

Good luck and let us know what you find.