1997 Ford F-250 front pads dragging on rotors

Thankyou for responding. I cracked open the left side bleeder valve and got a minutia of dribble. Thankyou.

Mr. Weizel, Thank you for you're response to my dillema.I am assuming that you want me to drive the vehicle with the booster disconnected to see how it brakes. Please note that I did not mention on my original complaint, that the front right caliper is still the original part, since we've owned the vehicle.I bring this up, because when I returned the core of the left one I just replaced, I happened to relate my problem to the owner of the parts store. He suggested my dragging problem and the imbalance of new caliper on left with original caliper on right, could be a contributing factor in this puzzle. The last two pad changes, I observed that the left set of pads wore down visibly greater than the right side of pads, (approx. 1/8") difference, but equally worn, inner and outer. That is why I never bothered to replace the right front caliper, since I could see that the pads were worn equally, althougth thicker than the left side pads. His reasoning for the unequal wear was that perhaps the left side brakes were "working harder" to compensate for the right side brakes. He could not however explain the dragging problem. Thankyou.

Thank you again Jim The answer to your question is as follows: Replaced RH rotor and pads @ 113K. Replaced LH rotor, LH caliper and pads @ 123K. Replaced LH rotor, caliper and pads, front brake hoses and master cylinder, all NEW parts, @ 126K.
I took the truck out about an hour ago and made several stops. Some at 30mph, regular braking, hands off wheel w/ no pulling. Some hard stops @ 35+mph, hands off wheel- Pulls to LEFT. As far as I can remember when I replaced the pads, I don't recall any difference between left or right when I compressed the calipers. I hope this helps?Thanks1

Thanks James for your help on this braking problem. I took your advice and began to focus my attention on the rear brakes, starting @ the rear wheels. Took the drums off and checked for leakage @ the wheel cylinders, polished drums and shoes, bent/ kinked lines, etc. There was dust in the drums as evidence of rear brake usage, but very little shoe wear for having more than 10K miles. All checked out otherwise, so I next focused on the RABS actuator on the frame. Since I had no way to trouble shoot it, I replaced it w/ a new unit and re-bled the entire system again (saturday 12/21). Road tested the truck and found that the front left caliper was still dragging, but the right side was intact. On Sunday, I replaced the left caliper again, re-bled the front, drove the truck for several miles and then once again checked the front- No more dragging caliper!
Here is my final summation: As you suspected, the front brakes were working fine at one time, the rears not receiving the full alloted pressure due to contamination in the RABS actuator, which @ some point, the front brakes were doing more of the work than necessary to compensate for the lack of pressure to the rears. This extra work on the front brakes caused the overheating problem, first to the pistons of the calipers, (which to my surprise were pnelolic and not metal). I believe the calipers, once overheating, started dragging on the rotors while the truck was in motion, causing the rapid wear on the pads and rotors. I believe the left side overheated always faster than the right, because of the short distance of line between the left wheel and the master cylinder.
In any respect, a very, very expensive and frustrating lesson to learn! Thank you so very much and have a wonderful Christmas! I hope that my situation can be useful to your cause! THANKS