My friend just put news rotors on his 99 xj. now his caliper wont retract fully on the drivers side. Installed new caliper, still wont retract after braking. Bled system, still nothing. any ideas? (by retract, I mean it is stuck in the closed position, not allowing the wheel to move.)

 

Hey there. probably no help. "New" caliper or replacement? I only mention because I recently had a problem with, best I can figure the old rings swelling. No leaks, worked, but didn't want to retract, just too stiff.
I would think if a new one won't slide in with the bleeder loose, it's defective.

 

Can you manually retract the piston while the caliper is completely removed and un attached from the vehicle?If it does then the issue is not with the caliper and only other things I could think would be something with the master cylinder,proportioning valve,ABS controller or something is up with the line.

I know, not very specific but those are some things to consider.Try bleeding the system again and make sure to start with the wheel furthest from the master cylinder.

 

Sounds like the brake hose on that side. Theres 2 layers in a hose, and over time the inner layer will tear, and act almost like a check valve, allowing pressure to enter the caliper, but then as the pressure tries to release, it catches a flap of the inner hose and holds the pressure in the caliper.

 

^^Hose is much more likely.