Alternator bolt...Snap!

[Broken_down?]

A few months ago my alternator bolt on the bottom broke. Thank god it broke enough for me to use some vise grips. Then it snapped again a few weeks later. This time I had to tap it out. Then guess what it snapped again a few days later! This time it snapped fairly far inside. So I tryed to tap it out again and ... Snap! goes the tap inside the dam hole I drilled in the broken bolt!!! So in a hurry I made a make shift bracket so I could run it for a few weeks. Well that turned into a few months. So this weekend I pulled the manifold and drilled a new hole in the tap that was broken and I bought a new set of taps that where supposed to be stronger. Well over the past few months rain got in the hole and caused some rust... So while trying to tap out the bolt, I snapped the new tap inside the old tap hole!!! Now I am up sh!t creek as I cannot find a dam drill bit strong enough to go through the the newest broken tap. Any one recommend a special type of drill bit that will go through the tap?

And why the hell am I breaking these bolts? All pullies line up straight. I don't think I am over torq'n them..?

Any ideas would surely help.

Thanks

Rich