2000 Sierra 1500 4x4 brake problem
 

Hi everyone, today I had to make a panic stop when a driver cut me off then stopped hard in front of me. It was at low speed but noticed right away my brake pedal went to the floor afterward, it was fine until this panic stop. I'm well aware of the rusted brakelines on these trucks, but it's not that, no leaking fluids. Has anyone experienced this? I don't want to start changing parts until I'm sure. I already have a fuel pump check valve issue and need to change the fuel pump, I have put that off because of the cost of parts, now this. The truck has been babied since new, and still looks and drives like a new truck even with it's 96000 miles. Last year I replaced all brakes and new rotors. I'm, hoping this is a master cylinder problem and not anything to do with the ABS system. Any help would be appreciated. Thanks

Does the pedal still go all the way to the floor? Even with the engine off? Does it still stop you? If it still has some brake action to stop you I would start by bleeding the lines to all four wheels. If you have no brakes since the panic stop it may very well be a master cylinder.

It's not likely to be a ABS problem if the ABS light did not come on. Did any other light come on?
(Like the "brake" light)

Gerald