Clunk from rear when hitting bumps.

javis20 · Post by **javis20** » Mon Mar 21, 2022 8:41 pm

Whenever I hit an unavoidable pothole, I hear and feel a loud clunk from the trunk area. Can be either right or left rear depending upon what wheel hits. Not sure if it's suspension related. This is happening when the top is up. So it's not the convertible top hardware. Could it be rear suspension bushings. 2011 Z4 60K miles....

B21 · Post by **B21** » Mon Mar 21, 2022 9:13 pm

AFAIK there's not much evidence to support worn bushes on the suspension..more likely shock absorber related IMHO..

mr.tourette · Post by **mr.tourette** » Mon Mar 21, 2022 9:23 pm

Sounds like a typical broken spring which is inevitable on all z4s

javis20 · Post by **javis20** » Tue Mar 22, 2022 1:26 am

I'll check the springs tomorrow.

flybobbie · Post by **flybobbie** » Tue Mar 22, 2022 9:41 am

When i first bought my car 9 years ago it had thump in the rear like someone banging the underside with a rubber mallet.
Mainly if one rear wheel was over speed hump.

I joined these forums back then. In the US there were quite a few with similar problem.
BMW tried to fix under warranty and couldn't.
I put up for six months until i found a 15 year old service bulletin (not Z specific). Haven't a copy now.
But it said talc the top and bottom spring rubbers.
I actually removed them, washed them, talc and replace.
I also turned the right spring 45 degrees anti clockwise, can tell it has S2 printed on it that should be out board.
Noises never come back.
Why BMW couldn't have done this, they should know all BMW problems and bulletins

flybobbie · Post by **flybobbie** » Tue Mar 22, 2022 9:43 am

I think the theory was the barrel springs pinch the rubbers on compression and rebound with a bump.
viewtopic.php?p=948309&hilit=rear+suspe ... mp#p948309

Busterboo · Post by **Busterboo** » Tue Mar 22, 2022 10:31 am

javis20 wrote: ↑Mon Mar 21, 2022 8:41 pm Whenever I hit an unavoidable pothole, I hear and feel a loud clunk from the trunk area. Can be either right or left rear depending upon what wheel hits. Not sure if it's suspension related. This is happening when the top is up. So it's not the convertible top hardware. Could it be rear suspension bushings. 2011 Z4 60K miles....

Had the same symptoms, including when top is up (but not down). Broken barrel spring. Cheap to fix.

mcbutler · Post by **mcbutler** » Tue Mar 22, 2022 11:05 pm

It could simply be a spring seat rubber that has worn through - easy to swap out on the rear

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