What would cause the "piston" not go back in (using a C-clamp)when changing brake pads?

Ford Explorer (99)...2WDR...REAR WHEELS... Its seems STUCK...nothing I do will get it to buldge. I have changes pad on other cars many times, but never run into this problem.


*doesn%26#039;t screw in...no parking brake set|||i just get a new caliper for the vehicle all four it cost more but it the easy way out.|||try taking off the cap to the brake fluid. if ther is too much presur it will not go in|||Don%26#039;t know.Thanks for the two points by the way.|||You%26#039;ve done this before so I assume you have the bleeders open. The brake piston is probably corroded. Good luck fixing that without replacing the caliper. It%26#039;s has disc brakes on all four wheels?|||sounds like it might have some rust or corosion on it.


But some systems do have a way of making the cylinder remaining in the out position to keep it from feeling a Judder when applying the brakes. but I only have seeen that type on foreign vehicles|||Are you sure it doesn%26#039;t screw in ? A friend and I ran into this on his rear discs some time ago. One side screwed counter clockwise and the other side was clockwise. It turned a 15 minute brake job into a 2 hour %26quot;I thought I was a good mechanic%26quot; session. lol