I have a 2 wheel drive 1992 Ford F250 with a 5.0 and E4OD transmission that's been having weird brake symptoms. It always had a rather low pedal until I found out my rear brakes weren't adjusted right. Once I adjusted them, I nearly went through the window because they worked so good. But now, over time, I have a good pedal/pressure, but it doesn't have much stopping power.

Here's what I've done:

All new Front and Rear brake shoes and pads
New Hardware
New Wheel Cylinders on both sides
New Calipers
New Rotors
Every line and hose is brand new
New master Cylinder
New Booster

SO basically, everything is new. I've noticed that it seems like the rear brakes randomly slightly stick. But sometimes (especially noticed in the winter) I've noticed the rear brakes don't work much. I went to stop and the fronts locked on a snowy road but the rear didn't seem to catch. But sometimes it does seem to catch. It's completely random. But I still have a great pedal and pressure. (And I know when boosters go the pedal is hard. The booster is new and it's not a hard pedal. It's actually perfect)

Recently the truck sat for about 2 months with little movement because I was painting it. I figured maybe rust built up while it sat so I took everything apart and cleaned it. No difference. Could this be the ABS unit thing? It seems like it's restricting flow of brake fluid. I heard something about pulling out the fuse for the ABS unit too see if it stops any better because it's in a "Neutral Mode". But I honestly don't know if that's true. Any suggestions?