I recently ended my 17 year BMW ownership run and bought my first Mercedes last month. It's a 1993 500SEL with 89k. It needed some new rear rotors and I noticed a rear thumping sound on bumps mostly on the passanger side. The next thing I tackled, based on all the threads here was the rear spheres. Needless to say, 2 new spheres and 240 dollars later I still have the thump. (by the way only one thread mentioned lowering the exhaust to get the removed and new sphere in and out on the drivers side, anyone reading this as it relates to spheres be prepared to do so). Anyway, My next guess and approach would be to battle either the shock bushings, coil bushings, frame bushings or is there a rear differential bushings? I hate to just start stabbing at "my" ideas of what it might be. Any advice on diganosing any of those next steps to lead me the right direction? I get the thump on potholes and manhole covers etc. in the road. It seems to be concentrated mostly on the passanger rear side but I am still listening to be sure.
Thanks,
Steve

1993 500sel

I went through the same thing with my '92 500SEL this past winter. You are going to have to replace the top strut bushing (or bump stop I think it is also refered to). The accumulators (spheres) that you replaced were the original culprits, but because of their failure the top bushings were damaged and all of the rubber is gone (hence the metal thump). More than likely only one is truly bad, but since they are not all that expensive I would recommend doing both. Good luck!

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1996 SL320 97K miles
1996 C220 130k miles
1992 500SEL 170k miles <---sold
1986 300E 216k miles <---sold

OK, that's sounds good. In reading some other threads, Steve from Gainsville Fla. diagnosied a similar problem and suggested the same answer. That was the part I was going to chase next, some reaffirming helps. Is there anything special to do for the job in respect to the best way to go about it? (ie - Jack up rear end, bleed off some hydraulic fluid, unbolt the shock / strut, unassemble the bump stop from the shock, put new one on, reassemble the shock back on car? Any advice is appreciated. Funny, after a few weeks of driving it so far, I am more fimiliar with the underside rear of the car then the options on the dash.
Thanks, Steve

Don't know much about the 500SEL rear suspension, but I had a similar "clunking" when I owned an '84 190E. Turns out the top mounting bolt was loose on one of my rear shocks. Just a thought and hopefully a quick check for you.

Brian

Yes what you want is the upper strut mount #140 320 09 44

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician