broken diff bolt solutions????

[bookemss]

I keep breaking my front diff bolt on my 99 M3. (2 genuine BMW bolts in two weeks) I'm sure many of you know what I'm talking about. I know AA has a reinforcement kit, but $200 seems like alot of money considering it's maybe 10$ worth of steel. Has anyone made one themselves? I was also thinking maybe one could drill out the hole and install a longer & larger diameter bolt that passes all the way through and use a nut on the back. Has anyone tried it? At least the bolt would be easy to get out if it breaks!

I'm going to try to create a reinforcement bracket of some kind before I resort to the drilling it out idea. If anyone has any schematics or suggestions please let me know. Once I have it figured out I will be sure to share my results and designs for FREE...thats right FREE. I'm sick of people getting rich from our misfortunes.

Oh and before someone says it. I DON'T drag race my car! But i do Autox.

[bookemss]

ok I think i 've figured it out. I completely removed the differential on Thursday night, dropped it off first thing Friday morning at a machine shop and had them drill and tap the front mount hole out to a 5/8 standard (course thread), I then went to a bolt supplier and picked up an L9 grade bolt of the same length as the BMW bolt. I also picked up a 21/32" drill bit (the size up from 5/8) and drilled out the mounting bushing on the rear subframe (use tons of lube, it's aluminum so lube helps to keep the bit from biting). I bolted it all back together and used blue locktite on the new bolt. So far, so good. I have brand new falken Azenis tires and I autocrossed and drag raced my car this weekend and I haven't broken anything. Which for me is a huge deal because I used to break the bolt everytime I autox'd. All together it cost me $45.00 canadian. Which is probably about $25.00 USD - including the machining.

The machine shop had some other ideas if this doesn't hold up, but with my sticky tires and my aggressive driving with no problems I think this problem has finally been solved once and for all