WHILE DRIVING 15 MPH, MAKING A SUDDEN STOP, VEHICLE'S BRAKE SYSTEM SHUTS DOWN. AN INDEPENDENT MECHANIC TOLD OWNER THAT THE ROTORS WERE RUSTED AND THE REAR CALIPERS WERE BROKEN OWNER STATES THAT WHEN SHE TRIED TO BRAKE THE PEDAL WAS MOVING BACK AND FORTH AND SURGED SUDDENLY. THE FRONT BRAKES WERE REPLACED PRIOR TO THE ACCIDENT . THERE IS A SERVICE BULLETIN OUT ON THE VEHICLE. DEALER HAS BEEN NOTIFIED ABOUT THE ACCIDENT. *AK