another rear end problem

[ROM3]

So i know theres crap loads of threads like this, but mines more of a figured out thing.....anyway, i've been having the rear end clunk when taking off normally from a stop light. Keep in mind that its been clunking for quite some time. Today i decided to go and check on my front diff bolt. It was loose and i went ahead and torqued to 73lbs. when i got close to the click, the bolt made a loud **SNAP**. i was like, oooo crap!!! so i pulled the bolt out and luckily it came out in one piece. it was cracked in the middle though. why would the bolt just snap like that? was it because from that whoel time it was loose it just got weak? sorry for the confusing post but please take your time to read it. im way too tired to write perfectly.

[M///BMW]

do u mind taking a picture of were the bolt is supposed to go?

i honestly have no idea, and i really am suspecting this bolt to be my problem.....



it could be that the steel just got weak over time...no big deal, it is 10 years old, and goes through a lot of fatigue...

[ROM3]

http://www.realoem.com/bmw/diagrams/n/v/20.png
There you go man. #17 is the bolt that cracked today while i was trying to torque it down to what usually people say to torque them to, which is around 73lbs. Thank god it didnt break inside! it only got cracked and the actual threads kept it together and i unscrerwed it and got it out in one peice!

[Brent 930]

That bolt broke because the diff carrier the diff is supported in is a bad design. It sounds like you got very lucky considering. You need a diff support bracket (AA sells one) after you get a new bolt put back in so that doesn't happen again, because it will.

[RRSperry]

And lock tite isn't a bad idea either. 242 blue, not the 272 red.

[DADx2]

I personally would not use locktite. These bolts rarely back out when torqued properly, but in the event of a bolt break, getting a locktite'ed piece out is not going to happen. My recent bolt breakage resulted in an easy removal of the remaining piece. I will weld on my "Radowski" brace before my car is back on the road next month.

My .02