my left front brake gets dragged and at times it locked up. I figured that it would be the rubber hose because the left caliper pistion was operating freely and that the right brake is fine, it cannot be the master cylinder. After I replaced the hose, it still drags. Now, could it be the master cylinder? How do you tell if the master cylinder is going bad? (It has 183k miles on it, FYI.) Is there anything else that could have caused it to drag on left side? Air in system? It was fine and out of blue it started to drag without me or anyone touching the brake system?

thanks.

 

Maybe the caliper slide pins are seizing?