Spray some penetrating lubricant onto the screws of whatever the nut is attached to, then let it sit for a few minutes. This will allow the lubricant to work its way under the nut threads and will help loosen it.
Adjust the tightness of your vise grips so that when you close the jaws around the nut, it is extremely tight. Ensure the grip is tight enough that it will not slip off when you attempt to loosen the nut.
Close the jaws of the vise grips around the nut and twist the nut clockwise just a bit. This will help break the nut free and make it easier to loosen than if you had just attempted to loosen it first.
Twist the nut counterclockwise with your vise grips until it comes free.
Things You Will Need
- Vise-grip pliers
- Penetrating lubricant
- If the area you are working in is too small or not conducive to vise grips, you may also be able to use a hammer and cold chisel to loosen the nut. Place the chisel off-center on the bolt and strike it several times with a hammer. The bolt should bite into the metal and loosen the nut a little more with each strike until you are able to pull it off.