Wrenches won't work no matter how much force ... As you apply high heat via a butane, propane, or, better still, MAPP torch, the metal will expand and break the corroded bonds enough for you ...

We put together a list of torch-worthy jobs. Stubborn nuts and bolts are annoying, and what's worse is when the wrench slips off and you smack your knuckles against the wall or the side of a truck ...

heat the assembly with the acetylene torch, loosen up any corrosion on the threads by tapping with a hammer, then simply unscrew with your wrench! Everything is easy when you know how! Of course ...