I suggest hand wire brushing the threads as much as possible and then heat the bolt from underneath briefly with a propane torch.

Melt a little wax (from a candle) onto the threads and the wax will wick its way up into the nut, providing some lubrication.

Let it cool a little and then the nut should come off without too much trouble.

If the bolt heads are carriage bolts and they start to turn in the wood, take a thin cutoff wheel and grind a slot into the bolt head. Then, you can use a big screwdriver to hold it in place.

Cheers, Dean


Dean 'Rustoholic' Meltz
Lurch: 1927 1-Ton Chevy Cattle Truck
Old and ugly is beautiful! -- The Saga
Lurch's Gallery
Justin: 1928 Chevrolet AB Canopy Express
In the Stovebolt Gallery