Center-punch the rivet as close to the middle as possible, and drill a hole slightly smaller than the diameter of the rivet about 2/3 of the way through it. Insert a pin punch into the hole and drive the rivet out. You'll probably be bolting the replacement ball joint in, so sometimes it's necessary to ream the rivet hole out just a bit to get a snug slip fit for the bolts.
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!