The last couple of years I've been using a home made variation of rust penatrating fluid. You can look up Ed's red on google and come up with a more complicated formula but I've been using a mix of 50% automatic transmission fluid and 50% acetone. Keep it in a small bottle and give it a good shake before using.
yesterday I needed to get a brake drum off a scrapper that was all seized up. A little Ed's red and I was able to undue the brake cylinder from the backing plate and these two adjusting bolts from the bottom of the backing plate.
It never ceases to amaze me how well it works.
