The left front brake occasionally locks up during road travel under even light brake pressure and has to be manually released by taking off the tire and hitting the brakes back apart with a hammer. The slides and rubber portion of the brake lines have been replaced. Neither of those repairs has made a difference. The mechanic through that a new caliper was NOT needed, but that seems to be the last remaining part that hasn’t been replaced.
Also, the brake pads have been replaced. Is this a known issue with the 1998 F-150 and are there any suggestions other than replacing the caliper?
Replace the caliper assembly and the flexable line to it. A collapsed inner liner can also cause a caliper to stay closed.
The truck is 12 years old. These parts can be considered normal replacements after 12 years. Some folks would advocate doing the opposing side caliper and line too, simply because they’ve both lived the same life and brakes are so very critical to safety. I would not argue with those advocates.
The slides are not the only things in a caliper that can hang up. The piston is sealed around the outside by a “square cut ‘O’ ring”. That ring deforms as the caliper is pushed, and that ring returning to “square” is waht actually draws the piston back off the rotor. That mechanism can hang up too with age and wear.