Bolts become rusted like many types of metal when they are continuously exposed to moisture. Over time the metal finish tarnishes and then oxidizes, resulting in rust. The bolt becomes welded in place by the rust. Forcing the bolt to turn will cause the bolt to snap or the head of the bolt to snap off. It will also result in the hexagonal head of the bolt to become rounded, rendering any wrench or socket useless. The most common methods to remove a rusted bolt include using a combination of heat, lubricant, hammer and wrench.
Apply heat to the rusted bolt with a propane torch all the way around the bolt, which causes the bolt to slightly expand and then contract as it begins to cool. The expanding and contracting helps to loosen the bolt from the threads. Use a good-fitting socket to try to turn the bolt to tighten it further before turning it in the opposite direction to loosen it. Success may take more than one attempt.
Clean the rusted bolt close to the area that is threaded into, and clean the head of the bolt by scrubbing it with a wire brush. Spray it with a lubricant designed to penetrate between the bolt and where it is threaded into. Cleaning the head of the bolt helps to keep the tool that you use from stripping or rounding off the hexagonal shape of the bolt head. Allow the bolt to sit for up to 24 hours when you spray it with the lubricant. It can take time for it to penetrate enough to clean up the threads. Turn the bolt as if you are tightening it first, and then turn it back the other way. You may possibly need to spray the bolt and let it sit again before it turns and comes loose.
Place a tight-fitting wrench on the bolt, and hit the handle straight down with a hammer, which is best performed after you have cleaned the bolt and sprayed it with a lubricant. The force of the hammer helps to break the bolt loose from the threads. A closed-end wrench works better in this situation because it wraps around the entire head of the bolt.
If you break the head off of the bolt, you will have to drill it out. You can accomplish this with a metal carbide drilling bit and a high speed drill.
- Photo Credit rust image by andrej pol from Fotolia.com
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