Noises and clunking from Rear

[etxxz]

Had this in my previous E30 as well. I get noises from the rear like something was loose or broken when i drive over a rough road or hit a pothole, dislevel pavement and things like that.

mods:
560lb springs
Koni shocks
New OEM RTABS
IE green subframe
318Ti rear/5-lug w/ e30 e-brake assy/cables

Things i checked:
Rear Strut Towers: solid, mounts well bolted, no cracks.
Differential: mounting bolts upwards of 150ft.lb. Driveshaft bolts are real tight too.
Bushings: RTAB well, i used air tools on those when the subframe was off. Subframe IE Streets extremely tight.

Things i notice:
RTABS squeak sometimes when i lift and lower the car = normal
With the car lifted and with rims/tires on, if i hit the tire with my arm hard enough i can somewhat reproduce the sound. But it isnt nearly as hard. It seems to be coming from inside the hub as if it was shaking.

I have never done a wheel bearing, but they seem fine. I they don't make noises when i turn, drift, launch, e-brake and beat on them on a level surface.

WHAT COULD IT BE???

please help asap. I'm undergoing a 6.5hr trip tomorow..

[Jean]

Checked your exhaust / shields / driveshaft ?

[etxxz]

my exhaust shields rattle under 500rpm but that's a different sound. this is more of a clunk than a rattle. Driveshaft huh, the CSB and guibo are perfect. Bolts are fine. sounds definetly coming from the very rear of the car

[Mike@PureMS]

Any chance the spring is too short and becoming loose when the suspension droops?
When you lift the car is the spring still tight on top and bottom? If it's loose when you lift the car in the air, it's likely the spring is rattling when you hit a pothole.

[etxxz]

its a coilover and is not tight, but its impossible to take out w/o removing the shock...now, what about why it makes the noises during rough road...its not lifting...huh

[funcrew]

A long shot, but check the fluid level in your diff. LSD will clunk like a bastard if it gets low on oil.

[craz azn]

With the car lifted and with rims/tires on, if i hit the tire with my arm hard enough i can somewhat reproduce the sound. But it isnt nearly as hard. It seems to be coming from inside the hub as if it was shaking

Check your rear brake pads. Clinking in the rear caliper carriers? Mine does a similar noise too, but I'm too lazy to take the wheel off to fix it lol.

[qbuilt]

^^^^
Thats probally it. I had the same sound before. Only occuring over quick/sharp little bumps. Found the brake pads to acually be seperated from the metal backing of the pad. However I have also seen the caliper slides get all worn out and dry and make a very similar sound. Just grese the crap out of everything with a good brake lube or a high temp antiseize. Should shut it up.
If that doesnt fix it maybe you have something going on within the ebrake assembly(seperated shoe, broken spring,etc...)
Also check the centercap on your wheels, if you have center caps that is?

[kenika65]

exhaust tip hitting rear valance

[japspecvr6]

Im having this same problem as well.......

[etxxz]

def not exhaust.

check it out. crazn and qbuilt are on the right track. Found out my 5-lug ti rear doesnt have the brake pad holding spring/metalbracket thingy. I have new sliding hardware on the rear calipers but the missing "pad-holder" may be the problem. The noises cease when i step on the brake. This leads me to believe that everything else is okay and this is brake related.

for those interested. part #
e30 (88is) - 34211153199
318ti - 34211157046

[BimmerTom]

Good info, thanks for looking into this. I have the same problem, and my Hawk HT-10's rattle like no other.

Tom