Be cautious about using penetrating oil around brake parts. Petroleum based penetrants and brake rubber parts like wheel cylinder cups don't play well together. It also contaminates brake linings. Silicone type penetrants will be a little safer than using something like PB Blaster. Using a little bit of persuasion from an electric heat gun or a Propane torch, with the brake drums removed, plus the silicone penetrant is by far the best way to free up any sort of sticky brake hardware.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!