Cause if it does that, you have a hose that's collapsed internally. Caliper pistons don't usually get stuck on these trucks, because they are steel instead of plastic like some companies use. It's common on a truck the age ours are for the hoses (since most of them are still the originals) to deteriorate. Either they collapse inside or little bits of rubber break off and get places where they shouldn't. Another thing that can cause pulling to one side is if the tire is low or something in the front end is loose. More likely that the hose is bad and making the caliper stick.
When the hose collapses, the fluid can't get back up to the master cylinder like it normally does. When the fluid can't go anywhere, then the caliper piston can't retract and that keeps the pads touching the rotor, grabbing it really, if the piston can't move back in its bore any. If the brakes get held on for too long, they can catch on fire. I came close to losing my Burb because of this happening 2 years ago. We got the fire put out quickly, but it did burn up the right side front brakes.
