So, I was going to clean the caliper pistons as part of the front pad replacement. As I was squeezing the front brake lever I lost focus and didn't pay attention. Only one of the four pistons was moving and it popped out of the caliper body. Needless to say the brake fluid poured out too. I managed to gently re-insert the piston after a careful visual inspection and cleaning. I finished the rest of the cleaning and pad replacement and bled the caliper (Speed Bleeder to the rescue!). I bled an entire bottle of DOT-4 through that caliper. I'm hoping that the caliper is full and that there are no air pockets. The squeeze on the brake lever feels good. Did I get lucky? Is there something else I need to do?