How do you remove the rear brake pads on a 1994 Ford Probe GT V6?

You are probably unable to remove them because the caliper piston is pressing on the inside pad. You must NOT try to push the piston in, like your would in the front, with a C-clamp. Instead, you will find a 12mm bolt on the back of the caliper (unless someone has removed it). Take it out, and then you will find a recessed 4mm hex that requires an Allen wrench. This will back the caliper off and down to a flush position, allowing brake removal. There are several really good explanations of the entire process around the web.