The most common cause of a sticking caliper is the rubber flex hose, but since you changed that already, I'm worried you might have the next most common cause. Any chance the brake fluid got contaminated with a petroleum product like engine oil, transmission fluid, power steering fluid, or penetrating oil? If so, we'll have to weigh the value of the car to the cost to repair it.
The next time the brake locks up, stop on a slight incline, shift into neutral, place a block about a foot downhill of a tire so you don't look funny chasing after the car, then open the hydraulic system at various places to see where the brake fluid is being trapped. Start with the steel lines at the master cylinder, and hope that doesn't work. Next, open the bleeder screw on the sticking caliper. If that lets it release, get it to lock up again, then loosen the connection between the rubber flex hose and steel line.
If opening the caliper's bleeder screw doesn't work, look at the caliper's mounting bracket. Ford has used their share of miserable mounting designs that don't allow the caliper to slide freely. One pad can be fully released while the outer pad is being tugged against the rotor. The best you can do with some designs is to file them smooth and flat, and be sure all contact points are lubricated with high-temperature brake grease.
Saturday, November 7th, 2015 AT 7:44 PM