sway bar links replaced, still have noise
 

I replaced the rear sway bar links, but I still get the classic noise when hitting bumps, speed bumps, etc....

It sounds like the wood spare tire cover is vibrating up and down, or some plastic sound vibrating....

WHere else should I look. could it be my rear seat, or my spare tire, it drives me crazy, I thought the sway bar replacement would surely fix it..

I had a loose piece of plastic that went under the rear bumper of my 85 300D that made a rattle. Just needed a screw to fix it.

next
 

yes, that is what I am going to look at next, loose pieces of exterior pieces, trim, etc...that is more what it sounds like

muffler hangers sagging?
 

is the exhaust swinging and making contact & buzzing a heat sheild?

Just taking a guess

that might be it
 

I took out the back seat, and looked at the trim, the nuts on the top of the rear shock, and everything else, and it doesn't look out of the ordinary.

I got under the car and if I move the muffler by hand left and right I get metal on metal contact around the area of the where the transmission is, or the flex disc area (but toward the rear more) Should I try changing the exhaust hangers (including the metal stuff)

Worn out subframe bushings can allow some noise on bumps too. I don't know if the noise would match your description, but you could check them out.

Ball joints make a nice bucking sound when they get worn out. There are some stabilizer bushings that hold the bar away from the body that could be worn out/gone allowing some sort of vibration. Can you hear it more in the back or the front? My 124 has a belly pan that makes a flapping noise over bumps, I dont remember my 123 coupe having one, but anything's possible.

I would start by just replacing the rubber doughnuts, forget how many, a friend picked 'em up at the local AP store, for about three times the price via mail order.
Good luck.

There's 4 of them on the rear muffler. There are soft and hard ones available. Get the hard ones. You could also upgrade to hangars from an SL which have a wire core to keep the exhaust from falling when the rubber fails.

driving me crazy
 

The sound is coming from the passenger side rear wheel area as best I can hear.... maybe more to the middle of the axle.. it is only caused by bumps, the car rocking/swaying from turns, uneven roads, etc... It is not the CV axles, or sway bar, and I couldn't determine it was the nuts on the top of the rear shock...Visually, my muffler hangers all look good, but when I manipulate the exhaust I get it clanging on something metal around the differential area but It is not a metal sound....it is either suspension related, or vibration related right?

My best desription is it sounds like what I imagine the piece of wood covering the spare tire would sound like bumping up and down....(I removed the piece to rule that out already)

Differential mount and flex disks in good shape? How about the center DS bearing and bushing? Also, you were asked about the sub frame bushings. Have you checked them?

....and the winner is.....
 

Bad rear shock. I put in the new Bilstein Comforts in the rear this weekend, and problem solved. Noise is gone when going over bumps. Turns out $115 brought me piece of mind... not bad.

http://www.dieselbenz.info/wiki/index.php?title=Replacing_Front_%26_Rear_Shocks

check out this DIY link