Any tips on drilling out a transmission housing bolt?

[n3985]

Today my friends and I tried to remove the transmission on my 97 328is with a worn clutch. Everything went well until we got stuck on one of the starter bolts on the transmission (about 10 o'clock position). After about a couple hours of using extensions, diff sized breakers the bolt head finally snapped off. :mad

http://img3.imageshack.us/img3/6429/img0101pe.jpg

So next weekend I guess we'll have to pull the engine with transmission attached to get to rest of bolts and drill out this one :(

Anyone who has done this before have any tips on drill bit size or etc? Thx!

[FranklyIDC]

You need to use a left-hand drill bit to get that sucker out.

You need to first prep it by making a dent in the center, then slowly keep drilling. Once it bits, you should be home free. I had to do this on a bolt on my intake manifold

[flyfishvt]

I don't see what the issue is. You have a 97 e36 so that bolt threads into the starter flange. As long as you have the other starter bolt out you can pull the starter and the broken bolt stud will come right out with it. Then you can take out the starter and work on it on a bench. Even if you dont have a starter with a threaded flange if one end of the bolt breaks off the rest will come right out. That bolt is NOT threaed into the bell housing or even the engine block.

[n3985]

Checked with my friend and I got the bolt wrong, it was one of the large E12 on the bell housing so guess have to proceed with engine pull...

[flyfishvt]

No you don't. If the entire head of the bolt came off you can just pull the tranny and deal with the bolt after its out. You'll be able to get a good grip on it with vise grips once the tranny is out. Some guys actually cut long bolts off and use them for guides when they are reinstalling the tranny. That's basically what you'll end up with.

If its one of the lower bolts and you have a tiny piece of the head left on it take a dremel tool to it and grind off the rest. Once again....the bolts are not threaded into the tranny bell housing. the non starter bolts are all threaded into the block. One exception is the tiny hex bolt that holds the dust shield in place. That is threaded into the bell housing but its very very accessable. You could easily get a grinder on it and grind off the rest of the bolt head.

[n3985]

Thanks for the suggestions unfortunately the bolt head did not entire come off, only 2/3 of it :(

[flyfishvt]

I haven't found a bolt yet that I couldn't reach with a dremel tool. Even the top tranny bolts can be reached if you rake off the intake manifold

Just seems like it's worth a shot unless you are experienced at taking out engines