[chillywings]

Hi folks,

I'm struggling to diagnose this issue and hoping someone may have come across it before. First of all, here's a clip recorded while going over a bump section of road:
https://drive.google.com/file/d/1YyV...ew?usp=sharing

As a note, it hardly takes anything in the way of bumps for it to start making noise. It clearly comes from the rear of the car. I've recently replaced the rear upper control arms (but not the rear-ward most one with the eccentric alignment nut on it) and the rear shocks. I've noticed that the noise goes away on really cold mornings (eg single digits) until the car warms up. It also makes a squeaking noise that's not present in the clip that seems to have come about with the warmer temps.

Since replacing the control arms the rear wheels have no 12-6 or 3-9 play. HOWEVER, if I lift straight up on the wheel, it has a lot of play and seems to replicate the noise I'm hearing on the road. My suspicion is the lower control arm 'ball joint' aka bushing, but according to sources online suggest that if this were bad then there would be play in the wheel. I can't seem to find any info about up/down play. Also, if I grab the wheel and rock back and forth until the car starts to move (forwards and backwards) it also makes a clunking noise. This makes me suspect the trailing arm bushings.

Can anyone confirm or suggest sources for up/down play in the wheel? Thanks!

[marvinstockman]

Upper shock mounts cracked.

Shocks themselves.

You can troubleshoot components for noise by soaking them with WD40 spray, waiting for the spray to soak in, and then drive car.

Also, metal cracks in body structures can cause noise, and are nearly impossible to find. Been there, done that!

[chillywings]

Good lord don't scare me like that lol. But yea I just replaced the shocks. It seemed to help at first but now it's back to how it was. The upper shock mounts are after market so I'm going check those next and make sure they're snug. Been thinking about it more and I feel like that's the most likely culprit. The sound seems to come from pretty high up. And I tried hitting the bushings with WD40, had no effect. Going to go back over them now with some 303 so they don't dry rot lol

[TyroneShoelaces]

Originally Posted by chillywings

Good lord don't scare me like that lol. But yea I just replaced the shocks. It seemed to help at first but now it's back to how it was. The upper shock mounts are after market so I'm going check those next and make sure they're snug. Been thinking about it more and I feel like that's the most likely culprit. The sound seems to come from pretty high up. And I tried hitting the bushings with WD40, had no effect. Going to go back over them now with some 303 so they don't dry rot lol

I think I have the same problem. I re-installed my Bilstein B6 shocks after dropping my rear subframe and I think I put it together wrong. Super clunky and bouncy in the rear. Finding a clear instruction as to how it all goes together and upper shock torque on the foam mounts wasn't easy. I also swapped in the Dinan rubber mounts that came with a donor car I had for my swap. I don't know why I can't just do it like the manufacturer meant!

[lowrydr310]

I can't play the audio for some reason, but what you described sounds like a similar issue I'm having, and I haven't resolved it yet.

I never had any suspension noises but decided to refresh the struts/shocks and all the mounts since they were original with 130K miles on them. I used the OEM-equivalent Sachs rear shocks with the Monroe upper mounts that have firmer rubber, and Lemforder lower shock mounts. A few months after installation it started making a dampened rattling sound. I took the trunk liner out and retorqued the upper shock mounts but that made no difference. My next step is to inspect the lower shock mounts.

TyroneShoelaces you have the Dinan mounts which have a firmer rubber. This is similar to my setup - I wonder if this has anything to do with it?

chillywings If lifting the wheel up is making noise, it's possible that you have loose shock mounts, so start there and inspect lower and upper shock mounts. Don't forget to check where the lower shock mount attaches to the lower arm. However you mention "it has a lot of play" which implies there's a worn bushing in one of the rear arms. If you can feel the play it shouldn't be too difficult to isolate it, maybe with a helper lifting the wheel/hub for you.

[Mike K]

Interesting thread. I’m about to jump on my rear shocks for my 2011 328i e91. 100k miles. Which mounting kits though?

these:

https://www.fcpeuro.com/products/bmw...kit-e9xrsmkit2

or these:

https://www.fcpeuro.com/products/bmw...-monroe-907984

Obviously, the comprehensive kit is best I’m thinking but I thought I’d put it out there before I order Bilstein B4 shocks soon. I’ll do the lower rubber mounts in any event too.

Thanks!

[Nando_e90]

Can't play the video, but just for the records, my e90 had a metallic noise from rear when going over bumps, and ended up being the trunk. The little struts were already worn, so they didn't exert enough pressure so there were some play, hence the noise.

I say this just to keep it in mind.

[chillywings]

Hey guys.. well update on my end. So first of all, my car has these installed as the lower mounts in the rear:
https://www.turnermotorsport.com/p-5...r-shock-mount/

I took one of the rear shocks out yesterday as I was suspecting the upper mount was loose (also after market turner mounts paired with the lowers). Turns out that wasn't the case but my lower shock mounts have a crap load of play in them. In fact, once the top nut was loose, I could simply push the shock up and down from the bottom. Once I got the shock out, I stuck my finger in the ball and it has all kinds of vertical and lateral play in.

So pretty confident that's my issue, trying to figure out if I should replace them or go back to stock mounts. But this is obviously specific to having monoball lower mounts. I guess if the rubber mount was shot you might have a kind of similar issue but idk.

Thanks for the replies!