Here is some text and another link just in case anyone thinks I made up the whole "residual presure valve" thing. I didn't see an RPV mentioned anywhere in the brake section of the FAQs, (I might have just missed it, I have done that before) so maybeFords don't use one, uh,,, wait a minuite the text here specificly mentions Ford.... hmmm.

Remove Residual Valve
The residual valve holds ten pounds on a drum brake system when the brakes release to keep the spring on the shoes from collapsing the wheel cylinders. Residual valves can be found in the end of the cylinder in ford fruit jar single master cylinders, where the brake lines screw into the master cylinder on some dual cylinders, one in the rear line only on front disc rear drum systems, or in the combination valve rear line only. You can remove the residual valve from the master cylinder where the brake line screws in with a sheet metal screw. Screw it in and then pull. It will come right out.

http://www.tsmmfg.com/Troubleshootin...t%20and%20rear)

 

when i put on new pads on my front discs the caliper was to tight so i had to push the piston back into the caliper. Since the older pads were worn down the piston on the calipers pushed out more to compensate for the wore pads. I put i small piece of wood on the piston and put a clamp and tightened it to push the psiton back a few millimeters, so that the when i put in back onto the car it was just loose enough to let the rotor spin. They will adjust automatically when you drive it around, i would just make sure that they arent locked up to tight. Good luck