Posted by David Sherman on Saturday, September 16, 2006 at 5:27PM :
In Reply to: Help!! ....Snapped Bolts posted by Kevin in Rehoboth on Saturday, September 16, 2006 at 3:35PM :
You're lucky to have 3/4" of bolt sticking out. I would weld a nut onto the end of the broken bolt, being careful not to direct the torch straight onto the block. This has two purposes. One is to give you a way to put more torque on the bolt than you can get with vise-grips. The other is to heat the bolt red hot so as it expands and then cools it will break the rust loose. As it cools, but before it's cold, you might try the candle wax trick. Once it's cold, try to work it loose going back and forth lightly with a wrench. If it doesn't break free, put some Kroil or PB Blaster on it and let it set over night. If you are starting to move it a little bit with a wrench, look closely and make sure the bolt is actually unscrewing and isn't just twisting. The last thing you want is for it to break off flush with the block. I have found red heat on a stuck bolt or nut almost always breaks it loose, especially with some Kroil to help once it cools down. WD40 is useless, and an easy-out will only make the problem worse by leaving an undrillable broken easy-out inside the broken bolt. Drilling it out is also tough because the drill will tend to run off out of the strong bolt into the softer cast iron if it has a chance. Then you still need to get the remnants of the thread out. Try welding a nut on first. That might be all you need to do.