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Rear end clunk

Posted: 05 May 2017 16:11
by unicorn
Hi all I have a clunk noise from the near side rear axle when I'm on and off the gas and when parked if I rock the car it also happens jacked up doesn't seem to happen I'm hard of hearing so difficult for me to pinpoint noise. There is no play in the wheel and drives fine otherwise any ideas what I should look for and any tests I can do . E.g. Diff half shafts bushes etc
Thanks in advance
Chris

Re: Rear end clunk

Posted: 05 May 2017 16:40
by HDRider
I would check the bushings in the lower swing arms. It could be as simple as loose attachment bolts.

Edward Hamer
Petaluma CA

Re: Rear end clunk

Posted: 05 May 2017 16:45
by unicorn
Not seeing anything lose but if I hold the axle beam while rocking the car feels like the clunk is inside it or could be transferring to it

Re: Rear end clunk

Posted: 05 May 2017 20:27
by moestr7v8
Check the trailing arm bushes, if they are still the original rubber bushes then they are probably well worn, invest in some poly bushes, it certainly made a difference to my car.
Cheers
Moe

Re: Rear end clunk

Posted: 05 May 2017 23:32
by busheytrader
Whilst checking the bushes, have a close look at the floorpan and bulkhead around the trailing arms. The areas around there are rust traps and the bulkhead can part company from the floorpan.

I had a similar clunk due to cracks across both sides and had a weldathon sorting it all out. (It held up with the 2.0L engine but gave in soon after the V8 was fitted). Some of the metal was paper thin and disappeared when prodded with a sharp screwdriver :x Hopefully yours is a simple problem.

Adam

Re: Rear end clunk

Posted: 06 May 2017 06:07
by Hasbeen
The lower trailing arm fittings are supposed to have thick washers under the bolt head, & the nut. I can only suppose this is to spread the end load on the bushes, rather than distort the bracket & only grip the steel spacer tube.

I chased what is probably the same clunk in the 8 for months, before discovering a reference to these thick washers in a 1977 Leyland TR7 workshop manual.

Made up some really thick washers, [about 3/16 mild plate], when I could not find thick ones in parts shops, & the clunk disappeared as if by magic.

Hasbeen

Re: Rear end clunk

Posted: 06 May 2017 15:20
by FI Spyder
I remember reading that the holes where the trailing arms attach to the body can elongate which causes some rear end slop. A local guy who stuck a LS6 400+ hp in with Mustang running gear did some reinforcing to prevent that from happening. Metal is pretty thin there considering the forces it can take over time.

Re: Rear end clunk

Posted: 06 May 2017 17:22
by unicorn
Thanks for the replies hope to get under it properly tomorrow and try to find the problem these replies have given me something to aim at
Thanks again
Chris

Re: Rear end clunk

Posted: 06 May 2017 18:43
by Beans
Also check that the bolts aren't rusted solid to the steel inserts from the suspension bushes.
This can give the same noises because you can only tighten one end of the bolt (the nut side)
As a result of which the bolt head will over time wear out.

Don't ask me how I found out :roll:

Image

Re: Rear end clunk

Posted: 15 Jun 2017 12:58
by andyf
Check the fore and aft propshaft movement on the CV joints, mine was clonking on acceleration especially under load uphill. I could grab hold of it and slide it front to back and it would clonk. Fitted a new shaft yesterday funnily enough, transformed the car.

Re: Rear end clunk

Posted: 22 Jun 2017 09:16
by swordfishdani1960
Why don't you check the exshust ,may be the one of
Rubbers that hold it on have pereshed ,this could cause a clunk
when on the move ,why don't you bounce the back end when static
see if its there :D