Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: teahead on September 25, 2019, 16:41:55
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Going over bumps, sounds like something is loose or metal on metal contact.
I looked under there and can't find anything loose.
Is this a classic symptom of maybe a bad trans mount? Seems like it's coming under the floor.
Or bad king pins? I grabbed the wheel and it all seems tight.
Motor mounts?
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Hi,
typical clunks can come from
- a rear axle differential mount: https://www.sl113.org/forums/index.php?topic=806.0 or
- a loose or worn rear transmission mount: https://www.sl113.org/forums/index.php?topic=23157.msg204750#msg204750, https://www.sl113.org/forums/index.php?topic=25552.msg192278#msg192278.
...WRe
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Could be an exhaust hanger.
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Make sure your jack is securely in it’s clip in the trunk
No need to ask me how I know this....
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If it seems like its under the floor then could be exhaust. Grab ahold of the tailpipes and give them an up and down shake. Just don't burn yourself! Also make sure the e-brake cables aren’t making contact with the center muffler.
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Smaller chance it could be what's known as the clunk bushing. This is the one that's on the shaft that holds all of the hinged parts on the rear axle.
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Take a look at the metal heat shield above the exhaust in front.
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Also try greasing the front suspension. If the noise temporarily goes away then it is most likely worn front suspension parts.
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I’ve had various exhaust hanger problems you can usually find by getting under and shaking things. The one which haunted me for 2 years was a ringing sort of clatter that only occurred at 3k rpm. Finally one day I happened to hit an exhaust pipe with a wrench (or ?) and heard the same tone and my ears went to full alert. It was the two exhaust pipes contacting each other. I was able to pry them apart and no more unwanted sympathetic music.
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The usual culprit is the rear axle differential mount.
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Thanks!
I'm thinking the latter.
I've greased the hell out of the front suspension and rear diff. Grabbed the exhaust pipe(s) and shook it to hell; tight as a drum.
I'll keep looking, but probably either a trans mount or diff mount I'm thinking.
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The rear differential clunk is very distinctive. Makes you look around when it happens, and say what was that!
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My 280SL would have a hard metal to metal contact thump when I went over a speed bump and yes, it turned out to be the rear differential mount. It was totally collapsed! Never replaced in 45 yrs.
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Teahead, did you ever find the source of your 'clunk?' I chased a very similar sound for over two years, replacing exhaust hangars, differential mount, inspecting everything I could think of, to no avail. Pulled off the right rear wheel to inspect the brake caliper, thinking it may have been loose. While doing so, and tapping around with a rubber mallet on the axle, I heard "the sound." The retention springs holding my handbrake shoes tight were shot, and had no tension in them. Bingo! The brake shoes, while still in the correct position, were loose enough that whenever going over even small bumps, reflectors in the road, etc., they would be jarred enough to bang around. I went ahead and replaced the shoes, retaining springs, etc. with the Mercedes parts (I am five minutes away from the Irvine classic center). Silence!
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My 280SL would have a hard metal to metal contact thump when I went over a speed bump and yes, it turned out to be the rear differential mount. It was totally collapsed! Never replaced in 45 yrs.
Similar story here, I replaced the mount and the clunking stopped.
Before and after pics below.
Best
Mike
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I had the exact same problem after having my rear axle dropped for servicing. The truck mount was installed upside down and the rear clunked repeatedly. After my mechanic put the trunk mount right side up, the clunking went away.