W123 Back-End Noise - PeachParts Mercedes-Benz Forum

rmmagow · #1 10-23-2012, 02:46 PM

I am hearing what can be best described as a hollow rattle coming from someplace in back of my head. I thought it was maybe the doors not closing properly or windows loose in the frames. Not 100% sure it isn't but initial checking seems to point to them as being OK. Which brings me to the rear-suspension. What should I check for beyond totally shot shock mounts? I did just swap out some worn rubber donuts holding the exhaust system. It just sounds like there's something loose back there. Any ideas where to try some trouble shooting? Should I just replace the shocks anyway as I have no clue how old they are. I'd do all four in any case.
Thanks.

rscurtis · #2 10-23-2012, 05:19 PM

Check the sway bar links. They're inexpensive and easy to change.

Biodiesel300TD · #3 10-23-2012, 05:32 PM

I agree, check your sway bar links. They often make rattling noises when they go bad. Remove them and check the ball joints on either end of the link. They should have boots on them and should be stiff to move. If the boot is gone or the ball joint is floppy you need new one. They are cheap and easy to replace.

Diesel911 · #4 10-23-2012, 06:27 PM

I had a noise in the rear and it turned out to be some of the Junk that I had in the Trunk making the noise.

Codifex Maximus · #5 10-24-2012, 12:00 AM

If you haven't already, check your exhaust hangers too.

rmmagow · #6 10-24-2012, 01:39 PM

Ordered the links. Cheap part for a change. All new exhaust donuts too.

Stretch · #7 10-24-2012, 02:06 PM

Oh right now you've ordered the parts...

...here comes a mad idea from the east! =>

Not the sun roof then?

rmmagow · #8 10-24-2012, 02:55 PM

Ha, thought of that since I ran into this with my other 123. Nice and tight though.

Stretch · #9 10-24-2012, 03:04 PM

Quote:

Originally Posted by rmmagow

Ha, thought of that since I ran into this with my other 123. Nice and tight though.

Phew - I'm glad you got those parts now!

Silber Adler · #10 10-24-2012, 04:00 PM

My new 85 300d makes such noise. I think the suspension is tight.

The exhaust makes the exact noise when I shake it vertically and hear the rattle. The mufflers and pipes look like they are in new condition. I wonder if there is a bump stop missing. It is going to take some crawling around under it.

rmmagow · #11 10-24-2012, 04:06 PM

Quote:

Originally Posted by Silber Adler

My new 85 300d makes such noise. I think the suspension is tight.

The exhaust makes the exact noise when I shake it vertically and hear the rattle. The mufflers and pipes look like they are in new condition. I wonder if there is a bump stop missing. It is going to take some crawling around under it.

I know of one bump stop at the very rear. Mine still is ok after all these years. I think the links mentioned here can look good, feel good but still be no good. Something like 10 bucks each and easy to put in. My exhaust looks good enough and I can't get it to rattle. Car in general is in pretty good shape, needs these kinds of little maintenance for niggling problems.

Codifex Maximus · #12 10-27-2012, 02:24 AM

Quote:

Originally Posted by Silber Adler

My new 85 300d makes such noise. I think the suspension is tight.

The exhaust makes the exact noise when I shake it vertically and hear the rattle. The mufflers and pipes look like they are in new condition. I wonder if there is a bump stop missing. It is going to take some crawling around under it.

There is more than one type of doughnut. There's the one that actually looks like a doughnut and then there's the one that looks like a Greek Alphabet Theta. Kinda like an O with a horizontal bar. I figure that horizontal bar is both for reinforcement and for additional quieting.

YMMV