Thumping with rear suspension travel

[wertyu78]

Hello all

I've been chasing down a thumping/clunking in the rear suspension. It only occurs with suspension travel. RSM's just replaced(hoping that was the issue) but it only dulled the sound. They were bad so I am glad I replaced them.

This started happening just the other day. I was driving to a friends house and all was well. I got out and hung out for a bit at his place, and as soon as I left the problem started. No irregular driving or anything. Very strange... 1303313034


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[danewilson77]

Subframe bushings?

[wertyu78]

Subframe bushings?


I've toyed around with the idea that it's subframe related, whether it's bushings or possibly even torn.... but I doubt it. It didn't start while driving or hooning. Simply in between trips to and from a friends house, while it was parked.....

[Avetiso]

Can you isolate which side?

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[wertyu78]

Problem found. 13040


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[Oli77]

Is that a subframe tear?

[wertyu78]

Indeed.... Ordering subframe reinforcement kit, all new bushings, and various other parts now.


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[danewilson77]

I win. Sorry to hear my friend.

What's your mileage?

[NorCalZman]

oh wow. I have not read of many ZHPs having this issue. What kind of driving have you done?

[midlandtech]

Damn man that sucks I need to chase down the cause of mine still

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[wertyu78]

I win. Sorry to hear my friend.

What's your mileage?

I am at 136,xxx miles now. I had the suspicion it was it, but really didn't want to admit it. You win.


oh wow. I have not read of many ZHPs having this issue. What kind of driving have you done?

I've not heard of any ZHP's with the problem either. Proves to show that we are not immune. I have done LOTS and LOTS of very spirited/hard driving for two years now.


Damn man that sucks I need to chase down the cause of mine still

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I wish you the best and hope it is simple!

[NorCalZman]

My sympathies. Please keep updating this thread (or a new one) with the process. Cost, what will be involved, pics, etc. Good learning experience for the community.

Did you have the subframe inspected for the beginnings of any cracks when you bought the car (ie. are you able to determine if this started to tear before or after you bought the car)? I feel like I have read that these tears develop over time rather than suddenly.

[Vas]

Wow that sucks. Was it clearly visible underneath?

[wertyu78]

My sympathies. Please keep updating this thread (or a new one) with the process. Cost, what will be involved, pics, etc. Good learning experience for the community.

Did you have the subframe inspected for the beginnings of any cracks when you bought the car (ie. are you able to determine if this started to tear before or after you bought the car)? I feel like I have read that these tears develop over time rather than suddenly.


Thank you very much. I will continue to post here and likely will post a new thread for this repair. All costs and work involvement will be documented.

I did not. I purchased it from the second owner (who purchased at 20k miles) whom was a banker and didn't drive the car hard at all. Damage was more than likely caused by me and my driving. Oh well...

[customcracka]

Wyatt - Is there anything on that car you haven't taken apart now?

[dVeLoPe]

Cost to repair the subframe on my M3 was $4800$ at a local BMW body shop BMW offered 50% and it would have been 2400$ out the door.
with a new subframe floor welded in (and I was going to use a TMS/HPF kit aswell for future safety) but was not worth it so I parted with the car.

THIS IS THE VERY REASON I am now on the fence about purchasing a ZHP or just saying goodbye to my favorite body style BMW... damn unibody defect!

[danewilson77]

This is the only zhp I've ever seen/heard of having this problem.

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[NorCalZman]

This is the only zhp I've ever seen/heard of having this problem.


Same here. Unfortunate honor to have, eh?

Whats strange is alot of people autocross these ZHPs too.

[Avetiso]

Super rare issue. Inspect before you buy, reinforce it, and you're good.

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[NorCalZman]

Was there a time limit or mileage limit to the BMW warrenty on this? It might not hurt to contact BMW about this and maybe theyll split the cost.

[customcracka]

Why would the standard e46 have this issue and the ZHP not?

[QC_ZHP]

I think it was a major issue on the early e46's (99-01) so that counts out ZHPs

[stephenkirsh]

I haven't heard of it being an early model vs late model issue like the front control arms.

Can anybody confirm?

[QC_ZHP]

This is just from a quick search, but it mentions how rare subframe issues are on facelift cars

http://forum.e46fanatics.com/showthread.php?p=12207558

Granted, no solid facts, but I think the consensus is that it's not as big of an issue as it was on prefacelifts

[Hornung418]

Was there a time limit or mileage limit to the BMW warranty on this? It might not hurt to contact BMW about this and maybe they'll split the cost.
My guess is that Wyatt's car is too far past stock for BMW to consider it.

[LivesNearCostco]

Definitely happened more on the early E46s... after some point (2001? 2002?) BMW made the rear floor pan stronger, or used a different brace to help distribute the subframe's load on the body, or something like that. What Wyatt shows is the type of crack that scares me, one that is hiding under the grime or undercoating. I look at my subframe area often and haven't seen a crack but worry one could be hiding, and you can't see the area around the front subframe mounts without first removing the brace and maybe some other parts.

I might be pulling some of the parts off later today in a rent-a-lift garage as I try to replace my diff bushings. Will check again for cracks, maybe even lower my subframe a little to get a better lock.

I think BMW repaired these under two policies: 1) Goodwill repair under warranty, 2) Settlement from class-action lawsuit. However the class action required owners to have BMW inspect before Dec 2010 and also required that rear suspension be close to stock.

[wertyu78]

Wyatt - Is there anything on that car you haven't taken apart now?

Just the transmission. Don't jinx me!


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[wertyu78]

Progress continued on a new a thread: Subframe repair and reinforcement, see below link:

http://www.zhpmafia.com/forums/showthread.php?t=12644



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[mLuMaN83]

Ouch

[PirateZHP]

Bump...

Wyatt (or anyone else), I have noticed that something in my rear gives a slight "pop" when pulling into the driveway. It isn't loud and you cannot feel it in the car. All this talk of subframe damage has got me scared. Anyone got other things for me to check first? Keep in mind that I am not a gearhead, so if you just mention a part, I may or may not know what you are talking about. Give me a little detail of where and what to look for.

Edit: I wanted to also throw out there that my driveway has this dip and then raise to get into the driveway which makes the rear suspension (usually on driver's side) travel pretty far. So, it could be that the strut is just maxing out... and so what I am really saying is that you can always tell me that I am over-reacting and it doesn't sound like anything.

[gmurphy]

Bump...

Wyatt (or anyone else), I have noticed that something in my rear gives a slight "pop" when pulling into the driveway. It isn't loud and you cannot feel it in the car. All this talk of subframe damage has got me scared. Anyone got other things for me to check first? Keep in mind that I am not a gearhead, so if you just mention a part, I may or may not know what you are talking about. Give me a little detail of where and what to look for.

Edit: I wanted to also throw out there that my driveway has this dip and then raise to get into the driveway which makes the rear suspension (usually on driver's side) travel pretty far. So, it could be that the strut is just maxing out... and so what I am really saying is that you can always tell me that I am over-reacting and it doesn't sound like anything.

I hear this noise occasionally on my car too. It was just inspected by my Indy and the entire GPC BMWCCA haha no issues to report. :)


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[PirateZHP]

I hear this noise occasionally on my car too. It was just inspected by my Indy and the entire GPC BMWCCA haha no issues to report. :)


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Word. I think I am kind of freaking myself out a bit... I'll poke around to see if I see anything that looks bad.

[danewilson77]

I would do a clean and inspect on your rear suspension. Specifically, just jack up one rear tire and pull the tire off, and pull that sides Shock, spring and strut mount. I'm betting strut mount. Have you guys ever inspected your springs? One of mine were broken noted after purchase.

I'd put my money on RSM's. If not, I'd then put my money on subframe bushings/issue's.

[PirateZHP]

I would do a clean and inspect on your rear suspension. Specifically, just jack up one rear tire and pull the tire off, and pull that sides Shock, spring and strut mount. I'm betting strut mount. Have you guys ever inspected your springs? One of mine were broken noted after purchase.

I'd put my money on RSM's. If not, I'd then put my money on subframe bushings/issue's.

Thanks, boss. I'll check it out.

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