ggaahahahah!!! suspension noises!

[CorvallisBMW]

I can't figure it out... I've been through all my suspension 3 times and still can't find the cause(s). Here's what's happening:

From the rear, there is a loud and distinct "thwack" or "clack" when going over small, sharp bumps (like expansion joints). It's not a deep sound like a thud, but higher-pitched; like 2 small hard components smacking in to each other. I've checked every nut, bolt and cable in the rear end but can't find it.

From the front, a distinct "squeak" when going over bumps on the left (drivers) side. Again I've checked everything under there and can't find a likely culprit.

BTW I should mention I'm running GC Coils, Bilstien sport shocks, M3 CABs, stock sways w/ urethane bushings, Race Skids x-brace.

Any ideas?

[spike68]

Maybe check your subframe bushings for the rear.

As for the front, could i possibly get a little more detail?

[samiam3356]

Did you raise the rear subframe 12mm? If so, then did you do the same for the Diff?

[E30_fiend]

I would check the nipples on the trailing arm and chassis for marls of impact.

What size spring are you running in the rear? Condition of rear shocks?

As for the front, I would suspect that your poly bushings on the sways need some greasing. Use marine grease due to all the wet weather up in the PNW.


Taylor

[AndrewBird]

As for the front, I would suspect that your poly bushings on the sways need some greasing. Use marine grease due to all the wet weather up in the PNW.

I was going to say the same. Use LOTS of grease. It's surprising how much bushing can squeak despite greasing them.

Maybe the rear is a worn ring/pinion in the diff banging over bumps? Checking the endplay/backlash would tell you if that was an issue.

[CorvallisBMW]

Maybe check your subframe bushings for the rear.

As for the front, could i possibly get a little more detail?

They're only a few years old, but I will check on them best as I can without dropping the whole thing out.

Details on the front... It's hard to say exactly but it is absolutely a classic "squeak" noise. Not a "creak" or "groan" like I've heard before from urethane. My bushings are about 2 years old but I'll pull them off and grease them up just to be on the safe side.

Did you raise the rear subframe 12mm? If so, then did you do the same for the Diff?

No, subframe is stock aside from eccentric TA adjusters

I would check the nipples on the trailing arm and chassis for marls of impact.

What size spring are you running in the rear? Condition of rear shocks?

As for the front, I would suspect that your poly bushings on the sways need some greasing. Use marine grease due to all the wet weather up in the PNW.

Taylor

Rear is GC, 6" I believe? I can't remember exactly. Rear shocks are in good shape, maybe 30K miles. The upper shock mounts are Bimmerworld with the "lifetime warranty"

I was going to say the same. Use LOTS of grease. It's surprising how much bushing can squeak despite greasing them.

Maybe the rear is a worn ring/pinion in the diff banging over bumps? Checking the endplay/backlash would tell you if that was an issue.

I might try pulling the DS and checking it out, maybe I'll find something hiding under the heat shield. I also want to pull the rear discs and look inside the e-brake assembly, make sure nothing is loose in there.

[EyExR]

On the rear, get under the car and shake your muffler around. Is it hitting anything at all?

Front - I'll repeat what others have said, check your sway bar bushings. How long has it been squeaking?
I've also had the brake pad retainer spring squeak on me in the past...

[giantkeeper]

Any update on the rear?

I have had this issue since installing the GC's in my car. Not horrible at first, but since I downsized my tires I lowered the car more last weekend. Now it's worse and happening far more often.

I'll get her up this weekend and see what I can find.

[CorvallisBMW]

On the rear, get under the car and shake your muffler around. Is it hitting anything at all?

Front - I'll repeat what others have said, check your sway bar bushings. How long has it been squeaking?
I've also had the brake pad retainer spring squeak on me in the past...

Did the muffler check, nothing made any noise. The front has been squeaking for 2-3 months now, and I put the bushings in about 2 years ago. I lubed them up but it's still there :/

Any update on the rear?

I have had this issue since installing the GC's in my car. Not horrible at first, but since I downsized my tires I lowered the car more last weekend. Now it's worse and happening far more often.

I'll get her up this weekend and see what I can find.

Rear still clicks and clacks, yet I can't find anything loose or out of place...

[Hellabad]

Front:

Check for water internally in the Bilsteins. Seriously

Second idea: If you raise the car slightly, and the noise changes or goes away then the noise is from the internal bumpstop of the Bilstein.

Third idea: undo sway bar links (completely) and see if the noise goes away

Rear:

Loose rod end on sway bar link?

[CorvallisBMW]

^all good ideas. I'll have to give them a try.

[giantkeeper]

I peeked under the car today when I got home and identified a rear exhaust hanger donut bought the farm.


Was not the issue.