TL*THE CONTACT OWNS A 2004 TOYOTA SIENNA. WHILE DRIVING 40 MPH, THE CONTACT DEPRESSED THE BRAKE PEDAL, BUT THE VEHICLE DID NOT STOP. THERE WERE 30-40 YARDS BETWEEN THE CONTACT'S VEHICLE AND THE PRECEDING VEHICLE. THE BRAKE PEDAL EXTENDED TO THE FLOORBOARD. THE BRAKES GRABBED MOMENTARILY, BUT THEN BECAME "MUSHY." THE CONTACT CRASHED INTO THE PRECEDING VEHICLE AND CAUSED INJURIES TO THE OCCUPANT IN THE OTHER VEHICLE. THE PASSENGER'S SEAT BELT DID NOT ENGAGE PROPERLY, CAUSING THE PASSENGER TO STRIKE THE DASHBOARD AND SUSTAIN MINOR INJURIES. THE VEHICLE WAS DESTROYED AND TOWED FROM THE SCENE. THE FAILURE AND CURRENT MILEAGES WERE LESS THAN 55,000.