My 2000 xj has a front passenger break caliper that locks up every now and then under quick breaking. I began to notice the problem after a lime rock pit excursion. I don't know if i got some mud in the caliper or something. Its been like a year since the lime rock pit excursion. It would lock up randomly here and there in the past year. But, it seems to be doing it a bit more frequently these days. I was thinking of maybe lubing the caliper pin. Possibly a new caliper? I don't see any outer damage from rocks or anything

 

Good call!

 

That's what I would do. Since you waited so long you my not be able to rebuild it. But still worth checking it out.

 

Check or replace the brake hoses and always replace calipers in pairs. A brake hose can have a defect inside that will hold pressure like a one way check valve. You can spend a lot of time and money chasing your tail when it could be as simple as a bad hose.