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WARNING! All owners with lowering springs or modified suspension. ACTION REQUIRED if incorrectly installed!

50K views 49 replies 27 participants last post by  Elie Malak 
#1 · (Edited by Moderator)
Note: This thread is NOT pointing at any specific brand, vendor, or installer. This is about INSTALLATION.
The purpose of this thread is to inform owners of SPECIFIC INSTALLATION INSTRUCTIONS GIVEN BY BMW, and often missed by installers.

Failure to follow BMW instructions could lead into a potential disastrous failure shown in the following thread:
Could have been a disaster today... check this out!
Luckily no one has been hurt.
In this member avi8tir case, Bolt #2 shown in the image failed.
You can see those specific parts highlighted in BMW OEM installation guide.


The Part Numbers are:

2 Rear Shock Bolts Part Number: 33-50-6-779-488
6 Rear Mount Nuts Part Number: 07-11-9-905-374
6 Front Mount Nuts Part Number: 31-31-6-769-731


Special thanks to everyone contributing knowledge and information in this matter.
 

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#5 ·
Part number for the hex bolts is 33506779488.
 
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#17 ·
I have the worst luck ever, I just installed the KW-V3 one week ago on my car with out knowing about this and it isn't even mentioned in the KW installation booklet. As specified in the installation booklet from KW, we reused all the bolts and nuts that were on the stock setup. Could someone please clarify how many Nm should these bolts be torqued? I didn't understand what they meant by 31 31 1AZ or 33 52 1AZ? what do all these numbers refer to, thanks.
 
#18 ·
Thanks for posting this up. Just ordered my new nuts and bolts! That's going to save us all a load of headaches
 
#21 ·
Ok, I think I know what this is all about. It's not unusual that the manufacturer wants you to change certain screws or nuts, after opening them. The reason is most likely that they have applied thread locking fluid to these when assembled in the factory. If you clean the threads and apply the correct thread locking fluid, I see no reason to change any parts. Especially not any nuts. Some bolts/screws in very special cases needs to be tightened to the limit where the material starts to plasticize and that is the only time you need to replace any screws.
 
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#39 ·
When I went to order the nuts and bolts from dealership all their names started with, "Self Locking"...for all of them. So I think they are made in a way that the last couple of threads change shape as its tightened the first time and lock the nut in its place. That's why they need to be replaced as it will lose its locking mechanism when its reused.
 
#22 · (Edited)
The nuts seem precautionary, the bolt is a stretch bolt from what I gather, so similar to cylinder head bolts, they need replacing.
 
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#25 ·
Does anyone know if it's possible to losen and apply thread locking fluid to one nut at a time, in the upper front mount, without messing up any angle adjustments? Don't want to redo the wheel adjustments... but i want to make sure the nuts are properly secured.
What's the proper torque to tighten these nuts?
 
#27 ·
If someone could post the torque specs, that would be really helpful.
 
#28 ·
Front top nuts are 25 lb-ft, rear top nuts are 21 lb-ft.

The bolt on the bottom of rear strut is 122 lb-ft.
 
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#30 ·
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#32 ·
The dealership is able to do it. It's a very inexpensive fix.
The problem is you will never know when and where it's going to happen. I recommend reading all the posts on this thread to get a better understanding of why those bolts and nuts have to be replaced.

Good Luck.
 
#37 ·
Sure they can. I posted a DIY-thread. Look into that one.
 
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