PARKING BRAKE:DRIVELINE:AIR
THE HYDRAULIC PARKING BRAKE CONTROL VALVE MAY INADVERTENTLY ACTIVATE DUE TO MOMENTARY PRESSURE DISRUPTIONS WITHIN THE SYSTEM AND CAUSE THE PARKING BRAKE TO BE APPLIED, STOPPING OR SLOWING THE TRUCK UNEXPECTEDLY. CONSEQUENCE OF DEFECT: THIS UNEXPECTED STOPPING OR SLOWING OF THE TRUCK MAY INCREASE THE RISK OF A REAR END COLLISION SINCE THE BRAKE (STOP) LIGHTS ARE NOT ACTIVATED. ALSO, ON CERTAIN ROAD CONDITIONS THIS OCCURRENCE MAY RESULT IN LOSS OF VEHICLE CONTROL WHICH WOULD LEAD TO AN ACCIDENT.
Remedy: REPLACE THE PUSH-PULL TYPE BRAKE CONTROL VALVE WITH NEW OVER-CENTER CAM TYPE VALVES.
51,500 vehicles affected