Odd brake pedal problem

My vehicle has a 2000 Wrangler brake system (due to 35" tires, needed for improved braking). It was all working fine and then I attempted to use the Winch to rip out a bush. Holding the brake and powering the winch, the cable finally snapped (3/8 steel cable!) And it blew out a brake line. I repaired the leaking brake line and properly bled the brakes and everything seemed fine. Now, when stopping, the brake pedal works fine the first time you press it, but if you let off and press it again it goes down further. Let off again and it goes down further. Until it is at the floor. If you just press it once it is fine. Once stopped, then you drive again, the same situation. The only thing I can think is the seal in the master is doing strange things and the master cylinder should be replaced, but I do not want to just start swapping parts unnecessarily. I have grown used to the issue, but it is unsafe and my wife has driven the truck and is not happy. :-)