On my 1982 Ford F-100 pickup, I am losing brake fluid. Over the past year I have replaced front disc pads, new hoses, rear wheel cylinders, and re-built master cylinder. The front reservoir of the master cylinder constantly goes down. And the master cylinder body is usually wet almost like the fluid is coming out around the cap and seal. I have replaced the master cylinder three times in the last 6 years thinking that the seals were gone. Could there be some way that pressure is bleeding back into the cylinder to force fluid out past the cap? There is an "equalizer valve" in the line but what it does I ain't too sure. Any help will be appreciated.

If you are not using a flare wrench when undoing the brake lines, the nuts can become destorted and leak. Clean area thoroughly and watch where the leak begins.