This is what I had to do on my truck, not sure if this is safe or not, buy they were rusted on good. I jacked up the rear, took the wheels off, then put the lugnuts back on. I then ran the truck through first and second gear, then tapped the brakes a few times, then repeated. It finally came loose after the fifth time, and practically fell off.
EDIT: Just read now that you have all the hydraulic stuff off, I guess my suggestion won't be of much help.