My 89 300ce has had a occasional minor clunk from the passenger rear suspension when going over bumps for quite some time now. On Sunday I decided to have a look.

I removed the shock and took it for a drive and the occasional small noise was still there. I went under the car with a stethoscope while my son pushed the back up and down and isolated the noise to the sway bar link.

Easy fix I thought. I put the shock back in so I could drive the car while waiting for the links. After driving halfway around the block the rear end started banging and clanging going over bumps like I've never heard before. Loud, and coming from the whole rear end it seems.

I've removed the sway bar links and double checked the shock mount but the noise remains. It's not throttle or brake dependent and only occurs over larger jolting bumps. I can't duplicate it by pushing on the rear.

I used a floor jack under the differential to hold up the car while working on it. Did I mess up my subframe mounts? Any other ideas?

Jorg

It sounds like a rubber bushing is gone. When you picked up the car it allowed the weight to come off the bushing and it moved from the position it was in. Just a little, but that was enough.

A quick repair from the old days was to fill up an oil can with brake fluid and hose down all the rubber bushings. If the noise stopped you may not know which bushing it was but you knew it was a bushing.

Today I guess you could use WD-40 so you could skip the oil can. It would also make it easier for the lube media to get down into the bushing.

This is not a repair, it is just a good way to test for a bushing noise.

Also, take a look at your strut. If the cartrage, the shock that is, is oily looking then you will need to replace it. They can make a lot of noise when they go out.

Pooka

The W124 has a bushing in the rear that commonly wears out and causes squeaks when going over uneven surfaces or bumps. And clunks when putting the car in gear.
It is the rear wheel carrier bushing, also known as the rear control arm bushing, and others have called it a ball joint (it's not) but it does have ball bearings in it.
Do a search and there should be some info.
I just replaced mine a few weeks back. About $50 for the 2 sides.
You need a special tool to remove and install the bushings. I did not need the spring compressor I rented from Brian, as a floor jack did the job easier.
I bought the bushing tool to use, and I put it in the rental program.
About 2.5 hours of work for both sides. Less if you've done it before.

It will likely be the diff mounts which do wear badly particularily one if the two rear mounts, and it allows the diff to hit the floor.

So, do a search for installing new ones.