Oh most knowledgable Ford folks, on a 1998 F150 2 wheel drive 4.6 250k, the front brakes will drag under a specific set of circumstances; only in prolonged stop and go traffic with hot ambient temps. Rotors, calipers, rear shoes, drums, fluid, bearings, seals have all been replaced. This occurs only a couple of times a year, otherwise the brakes work perfectly. It starts out as a slight shimmy that worsens until you can smell the pads cooking and the wheels are hotter than hell. The truck will hardly move at times. The rears are normal. After the truck cools for hours, no symptoms. Any thoughts or experiences? Thanks.

 

Replace the rubber hoses between the frame and the calipers at the front wheels. The hoses deteriorate and swell up. This causes the hose to act like a one way valve that keeps the front calipers applied. Good luck!

 

Thanks, KRM02 your solution is much appreciated.

 

I had the same problem on my older f-150, i replaced the pads, calapier, still same problem. i replaced the brake hose and it fixed it.

 

I had this happen on a 1998 2x4 with 388000km on the front left. A mechanic told me the clamp holding the brake hose will rust so much on the inside it clamps off the hose. Hydraulic pressure forces the fluid through the hose when braking but is restricted when released. I cleaned the rust out of the clamp and the brake works fine.

 

If all that doesn't work, I would think about piston )-ring swelled up or rolled/worn. Pop the piston out (with air) and emery cloth (inside Caliper) and a new O-ring should do it.

 

Yep just had this. It was the hose. Wheel locked so I opened the bleeder. fluid came out and wheel was free. Replaced the rubber hose and works perfect now.

 

I always recommend replacing the hose when replacing a caliper. For the same reasons as have already been posted above.