I have a 1999 F150 supercab with the 330 V8 automatic and I have started to have trouble with the brakes here lately. It started by thumping, so I pulled the tires off and found that it is time to replace the pads. So I replaced the pads and had the rotors machined on the front. That fixed the thumping, but it still pulled to the passenger front. Pulled the tires back off and checked the pistons in the passenger front caliper and found they were fine. Went to the driver front to do the same and cracked the ring on the piston so I replaced the caliper on the drivers side (I guess they dont sell the piston rebuilds anymore).

Thought that would fix it once I bleed the brakes. Took it for a drive and it still pulls to the right while braking, but now will pull to the left once I let off the brakes.

Does anyone know what the hell is going on? Was there something common that happened with these trucks? The only thing I can think of is something like the proportioning valve, but not sure.

This truck has all new brakes across all corners. Any input is appretiated.

 

I would look for loose steering or suspension components. I have seen a bad tie rod make the truck pull while braking.

 

The rubber brake line the goes to the caliper from the steel one could be collapsed on the inside; working as a 1 way valve. Had it happen on BOTH of my 97's. Which did what you're describing. Give it a try

 

I agree with Madness ^

 

Thank you. I'll tell you what I find.