I have a 2003 f150 4.6. If I back up for any distance and apply the brake (as in down a long road or driveway) my rear brakes tighten up to the point that I have to loosen the wheel cylinder from the back of the drum. (inconvenient in the woods on a muddy road). I know that you can adjust the brakes this way but it shouldn't do it all of the time.
Don't know why its doing it.

Any thoughts?

 

Figured it out. The parking brake was not completely releasing on the passenger side. if would self adjust when backing, Replaced the right side parking brake control cable and life is good. seems adjusting the wheel cylinder didn't really matter.