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  #1  
Old 08-16-2002, 10:59 AM
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jhowton jhowton is offline
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Lound Clunk from Rear?

Two nights ago as I was driving home from work (2002 330i 5 Speed, SP with UUC Sway barbarians on medium setting front and rear) I took a right hand turn pretty hard, I downshfted to 2nd and accelerated away pretty quickly. As I got on the gas again just before the apex of the turn I heard a very loud clunk sound from the right rear of the car. It sounded like something snapped. there was no curb (and no curb rash on my rim), so I didn't hit that. I also didn't see anything on the road.

Last night I jacked up the rear end and took a good look at all of the suspension components in the rear. Everything seems to be where it's supposed to be with no visible cracks on mount points. It seems like I have more understeer now though especially under braking. It's not excessive but the car has lost that jittery steering feel at speed (road feel). Something has definately changed in the rear suspension.

Anyone have any ideas? Do these cars have any known failure modes when the rear sways are beefed up? I was planning on getting underneath again on Sunday , maybe remove the rear sway bar and see what I can see but is there anything specific I need to be looking for? Obviously this is a non-warranty repair because of the swaybars so I'd rather fix it myself if possible.

Thanks in advance.
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  #2  
Old 08-16-2002, 11:07 AM
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The HACK The HACK is offline
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Check your shock mount
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"Bench racing" about track times driven by professionals are like a bunch of nerds arguing which Princess Leia is hotter, the slave Leia or the no-bra jail-bait Leia. No matter how compelling your argument is, the plain and simple fact is, none of you will EVER get to hit that.
  #3  
Old 08-16-2002, 11:11 AM
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Kaz Kaz is offline
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Quote:
Originally posted by The HACK
Check your shock mount
The shock mount isn't that loud, and it certainly doesn't affect the handling of the car. If from here on out a continual clattering noise starts coming from back there, then you could have very well blown out the shock mounts. There's really no easy way to check without someone poking their head in the shock mount area while driving.

After having different rear clunks for months, I've got all of mine exorcised finally.
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  #4  
Old 08-16-2002, 11:49 AM
PA330i PA330i is offline
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I had a continual loud clunking in the rear with my UUC sways. It was noticable when I'd hit bumps, when I'd shift hard, and when the car's weight shifted from side to side. I didn't experience a change in handling though. I thought at first my sways were hitting the trailing arm (or control arm?), or perhaps I had a busted shock mount. I got underneath the car, but everything looked fine. I completely uninstalled the rear sways, relubed the bushings and lubed and tightened the endlinks. I then reinstalled everything and the clunk is gone. I talked to a local BMW tech and club racer who told me that the endlinks were likely the problem. According to him, it is common for them to begin to clunk (even loudly) over time. He also said that in his opinion, adjustable endlinks are better suited for the track than the street, because of the need for maintenance (but who wants to give up the performance?) The solution is to relube and retighten them. You might try this, since it's a good starting point for diagnosis. If the clunk is indeed your shock mount, you might consider replacing them with the beafier shock mounts from the E46 convertible. If handling is suffering, I wouldn't waste much time finding the problem...it might be a more serious issue with your suspension.
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  #5  
Old 08-16-2002, 11:57 AM
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Kaz Kaz is offline
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I replaced the shock mounts with M3 ones and the UUC endlinks (on RD bars) with stock ones on modified mounts to get rid of my clunks.
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  #6  
Old 08-16-2002, 11:58 AM
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The HACK The HACK is offline
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Quote:
Originally posted by Kaz


The shock mount isn't that loud, and it certainly doesn't affect the handling of the car. If from here on out a continual clattering noise starts coming from back there, then you could have very well blown out the shock mounts. There's really no easy way to check without someone poking their head in the shock mount area while driving.

After having different rear clunks for months, I've got all of mine exorcised finally.
It depends. You're right, that it will continuously make a clunking chatter, but when it's first ripped out, depending on how hard the failure is, you may hear a very loud thunk, or if it's a gradual deterioration then it'll be an increasing clunkiness.

And if the bushing has completely torn out it will affect handling.

Another place I'd check is the lower subframe reinforcement bracket (see Nate328Ci about this).
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"Bench racing" about track times driven by professionals are like a bunch of nerds arguing which Princess Leia is hotter, the slave Leia or the no-bra jail-bait Leia. No matter how compelling your argument is, the plain and simple fact is, none of you will EVER get to hit that.
  #7  
Old 08-16-2002, 12:07 PM
Ben Chou Ben Chou is offline
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Another thing is that you could have torn or snapped your sway bar tabs. Check those where you mounted the bars with the bushings.
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  #8  
Old 08-16-2002, 12:11 PM
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Kaz Kaz is offline
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Hey, I gotta question for Ben.

Did you ever figure out a way to keep the bar from hitting the rear subframe mount donut area?
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  #9  
Old 08-16-2002, 12:13 PM
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The HACK The HACK is offline
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I noticed UUC redesigned their rear bar to have only 2 holes and it's now a little shorter...I think Ben got one of the new redesigned bars that fixed his problem if I remember right.
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Quote:
"Bench racing" about track times driven by professionals are like a bunch of nerds arguing which Princess Leia is hotter, the slave Leia or the no-bra jail-bait Leia. No matter how compelling your argument is, the plain and simple fact is, none of you will EVER get to hit that.
  #10  
Old 08-16-2002, 12:15 PM
Ben Chou Ben Chou is offline
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Quote:
Originally posted by Kaz
Hey, I gotta question for Ben.

Did you ever figure out a way to keep the bar from hitting the rear subframe mount donut area?
Well since we last spoke I got a brand new bar from UUC with new bushings and endlinks. I installed those and discovered that the old end links were going bad, the helical Heim joints were allowing way too much play, thus in my thinking allowing way too much play side to side thus letting the bar hit the subframe mount. Now, I am not getting the bar hitting the mount anymore, but I am afraid that my shock mounts are toast as I have a constant clattering clunk when going over bumps and especially when in parking garages at low speeds when going over the expansion joints. My car is going in next week for the Sticky pedal and I will have them replace my shock mounts then. I wonder if they will upgrade to the better ones to avoid this happening again.
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  #11  
Old 08-16-2002, 12:16 PM
Ben Chou Ben Chou is offline
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Quote:
Originally posted by The HACK
I noticed UUC redesigned their rear bar to have only 2 holes and it's now a little shorter...I think Ben got one of the new redesigned bars that fixed his problem if I remember right.
I actually got the Three hole bar and set that thing to Full stiff. So......
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  #12  
Old 08-16-2002, 12:52 PM
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jhowton jhowton is offline
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Thanks for the tips guys, I'll let everyone know how it turns out.
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Current - 2012 135is DCT
Previous:
2009 Mini Cooper S 6 Spd
2006 M Roadster
2004 645i SMG
2002 330i 5 Spd
2000 M5
1995 M3
A bunch of cars not worth mentioning...
  #13  
Old 08-19-2002, 10:02 AM
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jhowton jhowton is offline
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Update

I removed the rear swaybar yesterday and inspected the entire rear suspension very closely. Everything looks and feels nice and tight with no visible cracks at mount points. All of the bushings look good. The only looseness that I found was in the swaybar end links. The bolt through the bushing at the top of both sides was loose and was allowing quite a bit of play at the top of the end links. I added a drop of blue locktite and retightened those, regreased the urethane bushings and reinstalled the swaybar. I set it for maximum tightness this time. I didn't have a chance to give it a shakedown because I spent the next two hours washing and waxing my wheels ("M" v-spoke). This morning on the way to work, the rear end seemed to feel pretty good, the oversteer seems like it is back with no clunks or noises, and yes, of course it rained.
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Current - 2012 135is DCT
Previous:
2009 Mini Cooper S 6 Spd
2006 M Roadster
2004 645i SMG
2002 330i 5 Spd
2000 M5
1995 M3
A bunch of cars not worth mentioning...
 

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