2004 Ford mustang 3.8 front passenger caliper not fully releasing. Can spin the wheel but very labored and immediately stops.

Have gone part to part replaceing everything (caliper, brake hose, rotor, pads, fluids) but the problem remains.

As soon as I bring the pistons down onto the pads the wheel doesn't spin freely. If I open the bleeder the wheel remains stuck. When I take the caliper off the wheel spins free again.

All clips are correctly greased and in position. The slider pins move...

Caliper not releasing driving me mad (help)