ive just bought a 1998 f150 nascar edition and my front disc brakes are dragging up to the point of smoking. ive had the truck for about a month now and so far ive replaced the master cylinder, both brake calipers, both brake hoses and have bled them all down maybe 900 times.

the truck never actually locks up completely but it seems like the caliper pistons dont release enough, with the tires off it take a good bit of muscle to turn the rotors both driver and passenger have the same problem

 

JAck the front of the truck up. Take off the tires. Have a buddy step on the brakes and release. Watch the brake system and see if you see the pads relax off of the rotor. Did you install new hardware with the Calibers? Mainly the slide bolts maybe sticking. Are the return springs working correctly? Did you bleed all 4 wheels or just the front? Make sure your brake lines are not twisted.

 

Yes I did replace the sliders, and they're greased up, none of my lines are twisted and Im not sure what you mean about if the pads are leaving the disc because disc brakes always have contact with the rotors.

 

Sorry I missunderstood, the pads do relax but not fully, as I said earlier to spin the rotor by hand take alot of strength, and yes I did bleed all my breaks every time, from rear passenger, rear driver and so on.

 

I have had to replace a few calipers on friends F150's due to this. I think it might be and internal problem with the caliper.

 

How many times will I have to replace them lol

 

I know this is an older post, but another thought is the adjuster behind the master. Never had a 98, but assume they are the same/similar to earlier models.
Unbolt the master cylinder from the brake booster and there will be a threaded rod. Screw that in a little.