alternator bolt broke

[unimportant]

The alternator on my 460 broke the top mounting bolt in 2. I had the alternator tested and it's fine. I've got to get part of the bolt out of the engine block. ANy ideas of what happened or how to prevent it from happening again would be appreciated. I'm also needing a suggestion of how to remove the broken bolt.

[sargentrs]

In the head or in the block? Not that it makes a difference just curious. Did it break off flush or is there a stub sticking out? The key is going to be patience and persistence. Center punch it and start drilling with a small bit first. Once you have a good starting hole, get a reverse cut drill bit. If that's a 3/8" bolt, use a 5/16", or as close to the bolt diameter as you can get and still have some good meat. Using the reverse cut bit, drill slowly and you might get lucky and it'll come right out. If not, then get a left handed thread tap and cut threads in it deep enough to get a left handed bolt in it securely. Use a good quality grade 8 bolt, spray it down with PB Blaster over several hours or days and start trying to back it out, working the bolt back and forth. Don't try to grunt force it out. You might have to heat up around the bolt with a propane torch. If you can't get it, drill it out oversize to the next largest size bolt and retap. I've had some horror stories using EZ Outs. I've never been able to use one successfully without it breaking too and then it's a PITA from that point on. No clue why it broke in the first place but when you get it out, replace it with a Grade 8 bolt.

[unimportant]

The update is that I've got the bolt drilled in the middle, but I having trouble with getting the extractor to grip. It broke flush with the block. I've used wd-40, but I'm going to try something stronger and probably add heat on the outside.

[tac]

You can go a little larger on the hole and/or tap it on top to get it to bite. I've heard of people welding a smaller bolt to the top of the broken bolt.

[aquartlow]

If the bolt is flush or just "proud" of the surface of the block and/or head AND you have access to a wire welder, you can weld a nut to the broke bolt through the center hole of the nut, then carefully remove it with a wrench. I had to do this on my upper door keeper on my ext. cab 2K SD, when one of the mounting bolts broke off when I tried to remove the keeper when the cable end went bad and the rear door of my wouldn't open. Once I welded a nut on the broken bolt it came out quite easily. I was sweating it big time, neither pliers or vice grips would budge the broken bolt. Good luck. Todd

[unimportant]

it's broken slightly to the inside,and I'm trying pb blaster. I don't have access to a welder, that would have to take place away from my apartment. I'll try to keep updates.

[unimportant]

I ended up taking the truck to a mechanic and having the bolt drilled out. My truck is running again.