ABS FAILED ON WET SURFACE,SPUN 450 DEG,AFTER SPIN FAILED TO STOP VEHICLE. HISTORY: APPOXIMATELY 4-6 TIMES OVER A NINE MONTH PERIOD, WHEN THE BRAKES WERE FIRST APPLIED THEY DID NOT APPEAR TO WORK. UPON RELEASING THE BRAKE AND REAPPLYING, THE BRAKES THEN WORKED. THEN OVER THREE MONTH PERIOD THE BRAKES BEGAN TO FEEL CHOPPY WHEN STOPPING. THE VEHICLE WAS TAKEN TO THE DEALER AND ALL FOUR ROTORS NEEDED TO BE TURNED (ONLY 10000 MILES ON VEHICLE). TWO DAYS LATER ON A WET SURFACE, GOING 16-20 MPH ON A RIGHT TURN WITH A SLIGHT UPHILL GRADE, WHEN THE BRAKES WERE APPLIED THE BACK END OF THE TRUCK CAME SPINNING AROUND IN A CLOCKWISE DIRECTION. AT 90 DEGREES THE BRAKE WAS RELEASED. THE TRUCK SPUN A TOTAL OF 450 DEGREES. THEN THE BRAKES WERE APPLIED HARD, YOU COULD HEAR THE SOUND OF THE ABS BUT THE TRUCK DID NOT RESPOND AT ALL, THERE WAS NO BRAKING ACTION. THE VEHICLE CRASHED HEAD ON INTO A GUARD RAIL. THE ENTIRE FRONT BUMPER NEEDS REPLACING. FORTUNATELY NO ONE WAS INJURED.