WHILE DRIVING CONSUMER STARTED TO APPLY BRAKES, AND HIT A SMALL POTHOLE. BRAKES MADE A GRINDING NOISE, PEDAL WENT STRAIGHT TO THE FLOOR AND VEHICLE DIDN'T RESPOND. HIT CAR IN FRONT. CONTACTED DEALER, SAID NOTHING WAS WRONG WITH BRAKES. THIS HAPPENED AGAIN 27 JAN 00. ANYTIME WHILE DRIVING ON AN UNEVEN SURFACE THE BRAKES WORKS INTERMITTENTLY. JUST HAD THE TIRES REPLACED. *AK