This weekend I replaced the front and rear rotors on my gf's '05 grand prix. Well, 3 of the 4 anyway as I had one bolt that absolutely would not cooperate. I will take this to my mechanic and have him loosen it for me. Anyway, that was the easy part. I replaced the front pads with no issues whatsoever as the pistons in them compressed easily and the new pads slid in perfectly. I was not that lucky on the rear calipers. Even with a c-clamp and placing a block over the piston to apply equal pressure, I could not get the rear caliper pistons to compress for the new pads. The rear pads weren't too worn so I'm not scared that she will be unsafe but what gives? Is this a common problem with an easy fix? I'd like to get the final rotor on and the new pads on the rear. Thanks!