Bad Caliper or something elce?

Cstoliker wrote:

westend wrote:
Yes, you need the pad ears to slide in their holders and, yes, good brake fluid in the system. What some may not realize is that this era of larger Ford chassis had significant problems with calipers sticking, It happens especially when rotors and/or pads are worn to the end of their lifecycle. There is something about the geometry of the caliper cylinder and the mating seal surface that causes them to stick in the extended position. I've repaired/serviced more than a dozen Ford trucks with the same problem. The ultimate fix was to replace the caliper and they should be done, at the least, in pairs.

So the old warn pads may have been the cause. I'll still do my line pressure test to confirm but that makes sense. Did the bad calipers you've seen from this stick randomly while other times work normally?

Instead of looking at the problem from one part being at fault, it's better to look at the failure of the brake system (in this case, sticking in a position) as a progressive failure and interrelated parts problem.
As the pads and rotor wear, the caliper extends and retracts at greater length of travel. The caliper cylinder is pushed further out so that the pads are in contact with the rotor. This puts the cylinder and its seal at a position closer to the outside of the caliper, a place where road debris and brake dust may have settled previously.
My theory is that the outer caliper seal and mating surface see more wear and that the close tolerance of the cylinder in the caliper cause the binding of the seal and/or cylinder. On my own Ford trucks, I pay attention to the caliper mud seals and I will clean that area and apply some oil or spray underneath the outer mud seal. Whether this buys me time or is especially effective is unknown. I've had mixed results. Later model Ford trucks have a different caliper and don't seem prone to the same failures as those from 1995-2002.
Hope this helps.