[JP Noonan]

PB Blaster.
Heat.
Bigger hammer.

Repeat.

Also try a ball joint removal tool, looks like a tuning fork on the end of a crow bar.

Of coarse if it is that rusted it may just break off, this happened to my friends 75 when he went to set the e-brake on day. It just came off in his hand, so use some common sense.