If its the nut that's giving trouble, a cetiline torch, heating it red, and jumpin' the mother out of the Heafty wratchet with a pipe on the of the wratchet for torke.
If the nut is off and the roter is stuck, get a 10 pound mall and wack it a few times to get the rust off. Don't dent the heck out of it, just wack it. It should come off.