I am having trouble with the front brake on my bike. The cliper does not seem to fully release, and the brake will drag. It is sometimes worse than other times. I noticed this while giving my bike a thourough looking over after a pretty hairy crash. My first thought was a bent rotor, due to the crash. But, I don't feel like this is a bent rotor because it is equally dragging the entire rotation of the tire. If the bike is on the stand, and I spin the front tire quickly, it will not make much more than 1 and 1/2 turns on its on. I have removed the caliper and pushed the pistons in by hand, and the wheel spins fine. After I apply the brake, it never fully releases, and drags. What could cause this?? I have heard of brake lines on cars partialy collapsing and not letting brakes fully release, but i have never run into this prob with my bike. Just looking for suggestions before I go ripping my caliper apart.