1999 Toyota Camry • 250,000 miles

I have toyota camry 99 4 cylinder - when I apply brakes, the car stops perfectly but then it cannot continue to keep hold for longer time and car moves ahead, in fact the brake pedal moves down. Again I have to apply brakes - again it keeps hold for 10 seconds or so and again looses grip. In order avoid this in traffic, I have to change the gear to neutral. Please advise what could be the problem.
September 7, 2013.

If the brake pedal is sinking under light pedal pressure and you have no external fluid leaks, the master cylinder is by passing internally and should be replaced.

Sep 7, 2013.