My buddy has been having a strange problem with his 275,000 mile 2003 F150 2wd. The right side caliper will lock up out of the blue and will not release for anything. We put 3 news calipers on it within a 4 week period thinking that we had a defective one but no change. I am thinking either a bad brake line or, more likely, the front abs block...anyone else been through this problem?

 

I did see an article saying that is series of truck is infamous for this problem primarily due to the front brake hoses collapsing internally...I know he never changed out his hoses just his caliper so I think that changing them would be a good first step.