[moomar55]

Hi everyone, I'v been using these forums for ages and they're great but this is the first time i'v actually posted so hello all!

Basically, i'm very comfortable working on cars and I'v worked on several BMW's before, but when working on my own one I'v hit a brick wall with what could be wrong! I drive a 2000 328ci.

I basically removed the rear left trailing arm and replaced the RTAB and wheel bearing. A few days after putting it all together I noticed a clunking noise which arises when the suspension drops over a small pothole or something. Going over a ramp even at speed doesn't make the noise.

Since then I'v replaced the strut top mount and I also realised the coil top mount was completely gone so I changed that too.

The RTAB's were Lemforder, Bearing was FEBI (Best I could afford at the time), Top mounts are Meyle HD and the coil top mount is BMW OEM. The noise is STILL there and it is really loud now though.

Does anyone have any similar experience? I don't know if changing the anti-roll drop links will change anything. Its not a tinny noise so I highly doubt its the disc guard. I'v checked the driveshafts and everything seems rock solid. I feel its also very unlikely that the noise could be coming from the bushings/ball joints on the trailing arm as its such a prominent noise.

I suspect that I may have accidentally overtightened the bolt that goes through the RTAB and holds the carrier in place. This thought sounds stupid but I'm completely stumped and its making me so very miserable!

Any help would be highly appreciated!

Thanks in advance fellow Beamer heads!

 

[fn42]

can you jump on the rear bumper and get the noise to happen? figuring out how to reproduce it outside the car will help you a lot in finding it. FWIW I had a similar noise and found out one of the sway bar endlinks was missing its bottom bushing

 

[moomar55]

When I was replacing the top mounts I shook the axle like a madman and I could hear a very quiet knocking, which made me think it was the coil top mount. But when I put the wheel on the noise was still there! The noise really loud, like a proper textbook clunking noise but its really loud now which makes me think its something serious. I think tomorrow I might just change the endlinks anyway. Its quite an easy/cheap fix. I just hope it sorts the noise out :/

 

[peytonracer4]

possibly the rear war bar bushing or end link

 

[moomar55]

So I changed the left rear end link and the noise is still there! I took the old one off and it seems like it was in very good condition. I also checked the bushes and they seemed very good also. I got the bushes so i'll try to change them at some point tomorrow provided I have the time.

I noticed that when I push the car side to side from the rear left quarter panel I get a very small knocking noise. I don't know if this is related. Any other ideas?

Thanks for your contributions guys!

 

[peytonracer4]

maybe it's not the suspension but maybe something inside your trunk is moving around or something under the car is moving around like your exhaust or something.

 

[vol96]

check your springs. They often break near the bottom coil.

it not the spring, then ditto on the drop link.

 

[moomar55]

Im gonna empty the boot/trunk completely tomorrow including taking the spare out and i'll go for a drive.

Here are pictures of the droplink I removed, as I suspected it was in very good condition but I changed it anyway for a Lemforder part again! The spring is also still in one piece, I just replaced the mounts and managed to take a good look at it! The paint has flaked at the bottom but no cracks or breaks!

I haven't changed the bushes on the anti-roll yet. Is it really worth changing now?

Regards

 

[vol96]

Just a thought, but that bolt you may have overtightened, could that be preventing free movement, causing a bind which when releases it causes your noise?

 

[moomar55]

Im starting to think it is! Today the noise was HORRENDOUS! Its gotten considerably louder and seems to be getting worse by the day! I emptied the trunk/boot completely today, folded the rear seats and even took of the trim and the noise is still very prominently there! I recorded the noise but its quite hard to make out! Ill upload it and link it here, but its a very loud clunking noise.

Would the ball joints/bush on the bottom of the axle be the problem maybe? I undid it when I was pressing the new bearing and RTAB in but I definitely tightened everything up. Im so lost :/

 

[moomar55]

So I FINALLY solved the problem! After losing my mind on what it could possibly be, it was basically the nut which goes on the end of the bold which holds the RTAB's to the carrier itself literally had the SMALLEST amount of play in it.

All I did was tighten the hell out of it and put it back in! I made sure to draw around where the carrier was on the chassis so when I bolted the 3 bolts back in I didn't completely destroy the rear toe! Frustrating how I ended up pretty much changing everything before realising its just a loose bolt, but its sorted now!

Thanks for your help guys, useful insight mentioned here!

 

[Archbid]

Thank you for posting your solution. Happy driving!

 

[vol96]

Which nut was it on the linked realoem diagram? # 12 ?

 

[moomar55]

Yeah man, number 12! I tightened it by hand really well but I feel it'll be worth taking it down and thread locking it or putting a Nylock but there instead to stop it from vibrating loose again! That bolt/nut takes a beating!

Hope this solution helps!


Sent from my iPhone using Tapatalk

 

[Megalocnus]

Yeah man, number 12! I tightened it by hand really well but I feel it'll be worth taking it down and thread locking it or putting a Nylock but there instead to stop it from vibrating loose again! That bolt/nut takes a beating!

Hope this solution helps!


Sent from my iPhone using Tapatalk

If you tighten it to speck (110 N-m), there will be no need to use threadlock or a self locking nut. It will also be a good time to read on RTAB bracket preload. That bracket has to be oriented in particular position in respect of the center of the wheel hub. It's covered well in the Bentley manual. There are also some good threads here.

Incorrect bracket preload can result in poor handling, especially at higher speeds.