Spray with PB blaster, let sit , spray a few more times. Let sit overnight.DGive it a shot but don't go nuts, it will break. If it doesn't loosen, heat the nut with a propane torch or MAP torch, till it smokes and starts to turn color. It will probably loosen up at that point. I have never had the PB blaster and heat method fail but it may take a few applications and reheating. One possible snag if if the handle on the shaft is plastic. It may melt from the heating