Strut Tower Brace Center Bolt Problem

kentgbr · 01-09-2015, 01:18 AM

While searching for an incessant rattle from the center dash area, I discovered that the large middle strut brace bolt near the firewall was not fully seated against the brace forked ends. The bolt was very tight, but there was still a sizeable gap between the washer and the braces. It looks like the threads were not fully cut, causing the M12x1.5x39 bolt to bottom out early. This is on a CPO car I just bought and it's amazing that it could have been this way since new. I've used a few thick fender washers to fill the gap for now and the rattle is gone. It seems the best fix would be to re-tap the threads all the way through. May do it myself or talk to a SA about it. Has anyone seen or heard of this problem?

Cloud9blue · 01-09-2015, 08:02 AM

My guess is the previous owner has the M3 strut bar, which I think came with slightly longer bolt due to the thicker strut bar mounts. I know mine came with a new bolt, but I never bothered to compare.

kentgbr · 01-09-2015, 11:49 AM

Quote:

Originally Posted by Cloud9blue

My guess is the previous owner has the M3 strut bar, which I think came with slightly longer bolt due to the thicker strut bar mounts. I know mine came with a new bolt, but I never bothered to compare.

Thanks for the response. I checked the bolt specs and it's the correct 39mm length. I added enough washers to bring the effective bolt length down to about 25mm. Only then would it not bottom against the bulkhead before applying force to the strut ends. I'd like to find out if the bulkhead should be threaded all the way through, allowing the bolt to extend to the other side. On my car, the threads stop about 1/8" short of going through, limiting the bolt travel.

nunodiniz · 02-05-2025, 02:36 PM

Could you tel me how you solved that?
I'm having the same problem.

I realize this thread is a bit old, but it was the only one I could find with this same issue.

tcphoto · 02-06-2025, 10:22 AM

Why did you bump a ten year old thread? Do you think they still own the car or would respond? Great first post rookie.

nunodiniz · 02-06-2025, 11:41 AM

Thanks.
I assumed that was the etiquette, and it doesn't matter to me if they still own the car or not.

Anyway, the solution for me was cleaning the thread on the frame. After that the bolt went in all the way and secured the bars.

The Nightman · 02-06-2025, 01:31 PM

Thanks for searching first and following up with your solution. Hopefully it helps future readers

01-09-2015, 01:18 AM	#1
kentgbr Member 30 Rep 344 Posts Drives: 2016 340i Sedan Join Date: Mar 2008 Location: Bay Area, CA iTrader: (0)	Strut Tower Brace Center Bolt Problem While searching for an incessant rattle from the center dash area, I discovered that the large middle strut brace bolt near the firewall was not fully seated against the brace forked ends. The bolt was very tight, but there was still a sizeable gap between the washer and the braces. It looks like the threads were not fully cut, causing the M12x1.5x39 bolt to bottom out early. This is on a CPO car I just bought and it's amazing that it could have been this way since new. I've used a few thick fender washers to fill the gap for now and the rattle is gone. It seems the best fix would be to re-tap the threads all the way through. May do it myself or talk to a SA about it. Has anyone seen or heard of this problem? __________________ Present - 2016 340i, Alpine White, Black, M-sport, 6-spd, Track Handling, Tech pkgs Past - 2011 E90 335i, Alpine White, Ivory, Sport, Premium, Steptronic Past - 2008 E90 335i, Titanium Silver, Dakota Grey, ZSP, Steptronic, 6FL, Wagner FMIC, Bilstein B12 Pro-kit, M3 control arms, SS F/R brake lines
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01-09-2015, 08:02 AM	#2
Cloud9blue Brigadier General 720 Rep 3,253 Posts Drives: around the potholes Join Date: Aug 2008 Location: NY/NJ/MA iTrader: (13)	My guess is the previous owner has the M3 strut bar, which I think came with slightly longer bolt due to the thicker strut bar mounts. I know mine came with a new bolt, but I never bothered to compare. __________________ 09 BMW E92 335i: [I] Top Mount EFR 7670 / Dinan / AP Racing / Wavetrac / TC Kline 07 BMW R1200S: Shine Yellow / Akrapovic / Ohlins 19 Volvo V90 T6: R-Design / Bowers & Wilkins / Polestar Optimization 08 Porsche 997 Carrera S: 6MT / CXX / PSE / Tractive DDA
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02-05-2025, 02:36 PM	#4
nunodiniz Registered 3 Rep 2 Posts Drives: BMW E91 320D 2007 Join Date: Feb 2025 Location: Portugal iTrader: (0)	Could you tel me how you solved that? I'm having the same problem. I realize this thread is a bit old, but it was the only one I could find with this same issue.
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02-06-2025, 10:22 AM	#5
tcphoto Brigadier General 4525 Rep 3,336 Posts Drives: E92 335i 6MT Coupe Join Date: Dec 2009 Location: Nashville, TN iTrader: (1)	Why did you bump a ten year old thread? Do you think they still own the car or would respond? Great first post rookie. __________________
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02-06-2025, 11:41 AM	#6
nunodiniz Registered 3 Rep 2 Posts Drives: BMW E91 320D 2007 Join Date: Feb 2025 Location: Portugal iTrader: (0)	Thanks. I assumed that was the etiquette, and it doesn't matter to me if they still own the car or not. Anyway, the solution for me was cleaning the thread on the frame. After that the bolt went in all the way and secured the bars.
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02-06-2025, 01:31 PM	#7
The Nightman Cometh 1335 Rep 1,457 Posts Drives: Boy's Soul Join Date: Jul 2016 Location: Boy's Hole iTrader: (4) Garage List E90 LCI "330i& ... [10.00]	Thanks for searching first and following up with your solution. Hopefully it helps future readers
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