bump noises from rear suspension or the rear area

[xmb116]

i have a 280SEL 1978 model,
when i go over ruts or bumps there are definite bump of knocking noises from the rear.
there are no leaks from the the rear shocks or no signs of weepage at the base of the shocks.

the car has sls

david

[robertd]

Check the exhaust rubbers and mounts are all in good order, the usual culprit is at the tail end the 2 rubber rings stretch and sag over time this allows the rear muffler to bounce around hitting the underbody.
Rob

[Rimas]

Could also be the sway bar link bushing. Apparently makes a dull thud over bumps, that's what my mechanic said my clunk was. That reminds me I have to fix that soon!

[Squiggle Dog]

I was having the same thunk, and it turned out my shocks were dead, despite there not being visible leakage. It could be possible that the nuts on the top of the shock absorbers loosened up.

[xmb116]

when you bounce the rear end of the car there are no noises and the car stabilizes very quickly, it does not sag at the rear either, i will check the exhaust by pulling it up to the base of car to see if it makes a noise.
i had to pull the back seats out to locate the shockies (how hard is it) any way the nut was tight and when you push the car down several times no noise is heard.
can the shocks just fail? the car has done only 102,000 and is 1978 model

[xmb116]

can you guys advise if there is a work manual available to show how to change the shockies if need be??
thanks

[WGB]

With the exception of having to remove the rear seat ( You want to try this by yourself with the electric reclining rear seat option) the replacement of the shocks is very simple.
Support the rear suspension arm so that the shockie isn't in tension then - Two nuts at the top and a couple of bolts at the bottom and slide the old one out from underneath.



What can cause noise is that
1)the top shockie bushes weaken and a gap starts up in the rubber which may not be visible from the top unless the arm is supported and the shock driven upwards a little. If left in tension on full rebound it may appear to be tight.
2)The bottom ball joint on the shockie can develop clearance.
3)The trailing arm bushes can wear and the arm start contacting the subframe.



Bill