I recently noticed a dragging in my front brakes. When I got home both front calipers were pretty darn hot. I have had a sticky caliper in the past but never both at once. Could this be the proportioning valve or the master cylinder? or something else all together?
thanks
Yes. Any of those could be the cause.But the caliper piston and the drive in caliper guide pins have been the most frequent cause of dragging front brakes on that type Ford brake caliper. Those pins should be replaced when the pads are replaced and they should be thoroughly lubricated with brake grease. And whenever the piston becomes extended against well worn pads it tends to get cocked in the bore and jam, often making an impression on the piston that causes it to fail if compressed and put back in service.
To determine if the problem is hydraulic jack up the front end, install a wrench on the bleeder of a caliper and have someone repeated apply heavy pressure on the brakes and then release the pedal. When the pedal is released the wheel should be turned without excess effort. If the wheel cannot be turned open the bleeder while trying to rotate the wheel and if fluid exits the bleeder and the wheel immediately turns look upstream of the caliper at the hoses, proportioning valve and master cylinder for restriction.If opening the bleeder doesn’t free the wheel to turn the problem is in the caliper.
I should add that pumping the pedal several times unstuck them. I’ll jack it up and take a look. thanks
Many times the hose that leads from the caliper to the hard brake line is the culprit. The inside layer of that hose breaks down with age and a small piece can act as a check valve within that line. With a 19 year old truck it’s a good possibility.
But use @Rod_Knox 's test to determine if it is the caliper. This is the test most of us use to determine if the caliper is at fault and I’ve found it to be more common to be the hose that is the problem.
Yosemite
“With a 19 year old truck . . .”
You might want to recheck your math . . .
The truck is 29 years old, since it’s a 1987 model year, and it’s 2016 . . . last time I checked, FWIW 
Time flies 
I would grease the caliper pins and replace the hoses.
All excellent comments above. If I had to venture a guess, I’d say it was probably the flexible brake hoses leading to the calipers have deteriorated. That results in a one-way valve action when they collapse after you’ve pressed on the brake pedal, refusing to allow the brake fluid to move back towards the master cylinder and releasing the caliper pistons. Instant sticking brakes.
Sorry I got the math wrong @db4690 . I was using my wife’s method of figuring age.
I forgot her birthday one year and to try to cover myself I said, “But honey…you lie so much about your age…I thought we were skipping this year”.
It didn’t help, I had to buy her dinner all week.
Yosemite
Rod had the right answer the pads were down to the metal on the inside pad. I did not replace the pins since this is a farm truck and I’m cheap. I did apply a liberal amount of grease to them and I’ll cross my fingers the Pistons are not damaged.
Thanks guys
Thanks for the update. Good call RK! Glad you got your truck back on the road OP. Best of luck.