So here I am thinking I can help my bro with his rear brake job on his 96 RS. I get everything off, dry to depress the piston w/a c-clamp and I fail. I open the nipple to let off some pressure thinking it will close, Strike 2. At this point I was dumbfounded and we decided to give up for the night. Well he gets in the car and the pedal goes to the floor, Strike 3. We had to bleed the lines to get the air out so he could have brakes for the ride home.
What did I do wrong? Or what do I need to do to depress the caliper piston? I thought I knew how to do this but I guess not...