Are the bolts froze up in your parts truck or on your truck? If its froze up on your truck, just cut the bolts on the inside of the hangers, against the spring, and pry the leaf springs out. If theyre frozen on your parts truck, get a torch, like a propane coleman torch, and burn the rubber bushings out, and cut the bolts. If your installing a lift you may as well replace the bushings anyway. Buy bushings with the sleves and new bolts and nuts. The torch method could work on both trucks.