Tom Brownell, in his book, advises using a torch to heat up the SURROUNDING metal (not the bolt itself)hen trying to remove a stubborn bolt, or heating the nut itself when working on a nut.
If you think about this, you'll see what he is doing: making the OUTSIDE part larger via heat expansion, so that the stuck piece can be unscrewed.
Be reasonable in the application of heat though, and keep the torch WELL away from any gas can or other flammables (light cigarette lighters, solvent, etc!)
Tom says it is NORMAL for these old parts to be stuck after 50 years . . .
He also warns that pure brute force (like a breaker bar or imapct gun) can BREAK the part.
Jim G
