Tl * the contact owns 2007 gmc sierra 3500. while driving at speeds of 45 mph the contact depressed the brakes and the brake pedal fell further onto the floor board than usual before the vehicle would stop. the failure increased the brake stopping distance. the contact stated that the failure would occur whenever the vehicle was driven. the dealer was unable to duplicate or diagnose the failure eight times. the dealer advised the contact that the vehicle was safe to drive and there were no failures. the vehicle was not repaired. the approximate current mileage was 49,000 and the failure mileage was 2,000.