I just replaced my calipers because of this. Cheap. $100 for the parts and only 2 bolts to remove (on my Honda at least). You have to bleed to lines after though. In my case, the calipers develope a groove at the back of the piston which prevented the piston from returning all the way, leaving it slightly out causing the pad to drag on the rotor. YBefore, you could spin the wheel but only with a few lbs of force and once it was moving it would stop after only a 1/4 turn.