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A Broken Bolt

Q. I have a problem and need help and advice. I have a 1987 Ford F350 with a bad water pump, in the process of removing the old pump I found some very tough bolts to remove. I managed to get 2 of the last three off safely but the last one wouldn't budge, well I popped the head off the bolt. Good news is the water pump slid right off. Bad news is I can't get the old bolt out. There is a 2 inch casing that the screw goes thru before it actually threads into the block ( this is the 460 cu in engine).

I've been told to try and torch the screw to heat it up, and I've been told to do the block not the screw. Liquid wrench doesn't seem to penetrate far enough to the threads. Is drilling the only other option? I've never rethreaded a block and this bolt is like 6 inches long. So any and all advice is a appreciated and much needed.


A. You do have a problem TJ. Whenever I break a bolt I can usually be heard uttering colorful explicatives. The casing will prevent you from heating the proper place on the block to turn the bolt out. Whenever you use the trusty "heat wrench" never heat the bolt itself. It will get hot, expand and make it even tighter. Heat the area around it instead.

I would try going to the parts store and getting a spray can of CRC 5-56. I have found that it will penetrate deeper into the threads and dissolve the rust. Spray it on real good and let it sit for 30 minutes. Lock a large pair of vice grips on the bolt and move it back and forth a few times. Don't try to take the bolt out, just go about an eighth of a turn each way.

Then spray it again and wait another 30 minutes and do the bolt twisting thing again. Spray it again and work it back and forth and try to turn the bolt out. If it starts to move turn it about a quarter turn, spray it and turn it back. Keep working it back and forth like this until it comes all the way out. Once it's out, spray carb cleaner into the hole to clean it out.

If the bolt should break coming out, then drilling is your only other option. When you drill, take a prick punch and tap a dimple in the exact center of the bolt. Then drill straight through the bolt starting with a small drill bit and working your way up to the proper size. You'll need a tap the size of the bolt to rethread the hole.

When you tap the hole, spray the CRC 5-56 into the hole and work the tap a quarter turn and back off a half turn. If you don't do this the tap will bind in the hole and break. And believe me, there is no way you're going to drill out a broken hardened steel tap. Slow and easy is the key to doing this successfully. Rushing is a sure way to mess it up.

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