Clunk in rear of 3.0 CS

[taylorcom]

After years of putting up with a loud clunk when the right rear corner of my '72 3.0 CS hits a bump, I've decided to stop procrastinating & fix it. My question is how to tell the source of the noise?

I doubt it's the upper shock mount, as I took a close look at it a few years ago and it looked okay. But I could be wrong.

My best guess is a worn subframe bushing ("silent block"), but I want to be sure.

Does anyone have advice on determining the cause and the fix?

Please note: the noise has been stable over the past 10 years or so, not getting worse, and it occurs when I hit bumps in the road.

 

[afeustel]

Since the suspension is nearly identical to the E9 (except for the spring/shock separation) I would think a search on the main (E9) forum might yield some suggestion as I have seen this topic come up so many times in the past.

Shocks themselves can make noises but it is really hard to tell exactly what is causing the problem. If there are no obivous causes (bushings examined at every fitting), then all you really have left are the shocks themselves or the subframe bushings or swing arm bushings.

Good luck, wish I could say "check XYZ, this is the problem".

 

[taylorcom]

Right. It could be a lot of things.

Is there a way to visually check the bushings?

 

[taylorcom]

Well ... I just removed the back seat, drove it over a bumpy road, and now I'm pretty sure the sound's coming from the upper right rear shock.

 

[MMercury]

http://www.e9coupe.com/forum/showpost.php?p=11228&postcount=4

 

[taylorcom]

Ouch. I'd been thinking it was probably a bad subframe bushing.

Now it's time to remove the elephant skin ... and find a friendly welder.

 

[Arde]

Ouch. I'd been thinking it was probably a bad subframe bushing.

Now it's time to remove the elephant skin ... and find a friendly welder.

Mine made the noise for more than a year before the shock coming through the elephant skin.
Fixed it in San Francisco's Phaedrus per Bert's recommendation.
You can still save the skin...

 

[taylorcom]

In my case, the elephant skins near the upper shock bolts have multiple cracks on the top, but not their sides. The cracks radiate from the bolts. The shocks themselves haven't protruded, and seem to still work when I push down on the rear corners of the car.

The rest of the skin is intact, but feels brittle and prone to cracking.

 

[taylorcom]

Well, I haven't yet taken the trunk apart so I can carefully remove the elephant skin. But I just did some brake work on that side (passenger-side rear brake) and looked up the shock tower. I expected to see a disaster zone but it all looked intact ... no cracking was visible in the tower, top to bottom.

Maybe I've lucked out?

Even so, I still need to find the source of the clunk, which is accompanied by a rattling noise (which sounds like loose washers shaking on a bolt).

 

[HB Chris]

I had a rattle like that for two years. There was an unneeded washer on the shock piston under the mount that rattled.