Rear suspension clunl

[PatrickMcHugh]

I recently overhauled the suspension in my e30 vert. It got new control arms, sway bar links, Bav auto springs, Bilstein sports and most of the wear items replaced. I've got a nasty rattle coming from the rear suspension that sounds like something is loose. I've checked and double checked everything and it all looks OK. It's sort of a hollow sound that I thought was the convertible top banging around in it's storage area, but it's not. It seems to make the sound when the suspension is unloading. Handling is not otherwise affected and I can't seem to recreate the sound by jumping on the bumper or lifting on the car. I replaced the rear upper shock mounts which turned out to be shot, but it did not make a difference. Anybody got any ideas? I'm stumped and there's not much else back there to check. I've tried shaking the exhaust around, that's not it either.

[Adrian_Visser]

Rear subframe bushings. Jack the car up and inspect them.

[PatrickMcHugh]

They were pretty pooped, but definitely not responsible for the sound. I replaced them anyways and the sound still remains. If I run over a manhole cover, speedbump or even a pronounced dip in the road it sounds the car is going to explode.

Handling is for some reason not affected adversely.

[PatrickMcHugh]

BTW, it's not the exhaust. The trailing arm bushings have some cracking, but appear to be sound.

[jlevie]

Check the rear sway bar bushings. A simple way of reducing the search space is to remove the rear sway links. If the noise goes away the problem is in the sway bar. If not the problem is in the rear suspension. To further isolate the cause, remove the rear shocks.

[PatrickMcHugh]

Check the rear sway bar bushings. A simple way of reducing the search space is to remove the rear sway links. If the noise goes away the problem is in the sway bar. If not the problem is in the rear suspension. To further isolate the cause, remove the rear shocks.

I beat you by the punch by a few minutes! Great minds think alike. I removed the shock mounts essentially running the car just on springs. The noise is gone. I guess the shock mounts although brand new need to be upgraded to accommodate the stiffer shocks. Anyone found this before? I used MTC brand.

[jlevie]

Are you sure they are assembled correctly? Check the parts breakdown at realoem.com.

[PatrickMcHugh]

I've got the rubber donut, the big washer facing down, the bump stop with the bolts sticking up, the small washer facing up and the nut just like realoem.

[jlevie]

That would be correct.

[PatrickMcHugh]

I am not running that paper washer/gasket, could that do anything?

[PatrickMcHugh]

Alright folks, I nailed it!

It was a fucking piece of iron, presumably placed there to prevent the upset of balance since the battery is in the trunk. The front bracket broke and this thing was flapping around like a fish. Geeeeeeeez, that one almost drove me over the edge.