How to Loosen a Corroded Nut From a Bolt

Lubrication is necessary for loosening corroded nuts.

Nuts and bolts that stay exposed to the elements often become rusty. The rust causes corrosion which makes removing the nuts and bolts difficult because the nuts and bolts nearly meld together. Some mechanics and homeowners simply attempt to cut the bolt rather than attempt to remove it once it is corroded. Before resorting to cutting, though, there are some things you can try to loosen the nut for removal. Loosening a corroded nut from a bolt requires removing some of the rust adhering to the threads.

Things You'll Need

• Stiff wire brush
• Spray penetrating lubricant
• Wrench
• Socket wrench
• Breaker bar
• Hammer

Instructions

1. Scrub the stiff wire brush over the sides and top of the nut as well as the bolt threads. This removes the loose rust, and allows for better penetration of the lubricant.

2. Spray the nut with penetrating lubricant and allow it to soak for 20 minutes, especially where the nut meets the threads of the bolt.

3. Brush the nut and threads once more with the wire brush to remove any rust loosened by the lubricant.

4. Hold the head of the bolt with an appropriate size wrench or socket wrench. This keeps the bolt from turning while loosening the nut. If using socket wrenches, use the six-sided sockets versus 12-point sockets. The six-sided sockets give better grip.

5. Place an appropriate size wrench or socket wrench over the nut, and turn the nut counterclockwise. If necessary, slide a breaker bar over the wrench or socket wrench for additional leverage. A breaker bar is a hollow metal tube that slips over socket wrench handles.

6. Apply more penetrating lubricant if the nut fails to loosen initially. Bang on the side of the nut with a hammer to help loosen up rust. Avoid hitting the bottom of the bolt as this could cause the threads to compress. Loosen the nut again once the lubricant sits another 20 minutes. This is usually enough to loosen the nut.

Tips & Warnings

• Loosen the nut with an impact wrench, if one is available. Impact wrenches use lots of torque to remove bolts and nuts.

• Cut the bolt between the object and the nut with a hacksaw, if the nut does not budge at all.

• Avoid using heat unless absolutely necessary. The lubricant can catch fire causing other problems.

References

• Popular Mechanics: How To Free a Rusted Bolt