NHTSA Recall 78V008000
Filed by Motor Coach Industries, Inc. Component: Service Brakes, Air. Reported 1978-01-16. An estimated 527 vehicles are affected. Recall repairs are free at any authorized dealer.
Defect
THE INVOLVED VEHICLES MAY NOT COMPLY WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "MODULATED EMERGENCY BRAKING". THE "O" RINGS IN THE SHUTTLE VALVE MAY DEVELOP SLIGHT LEAKS IN COLD WEATHER. IN ADDITION, NEOPRENE WASHERS USED ON THESE "O" RINGS MAY EVENTUALLY EXPAND OR PUCKER IN COLD CLIMATES, MAKING IT POSSIBLE FOR THE SHUTTLE PISTON TO BECOME TRAPPED BY THE INNER-CIRCUMFERENCES OF THE WASHERS. THIS WOULD FORCE THE EMERGENCY BRAKES TO THE "ON" POSITION AND WOULD PREVENT THEM FROM BEING RELEASED.
What the manufacturer will do
THE DEALER WILL REPLACE THE TWO NEOPRENE WASHERS WITH GLASS FILLED TEFLON WASHERS THAT WILL NOT BE AFFECTED BY COLD CLIMATES.
Notes
VEHICLE DESCRIPTION: BUSES.SYSTEM: EMERGENCY BRAKES; SHUTTLE VALVE.CONSEQUENCES OF DEFECT: SHOULD THE EMERGENCY BRAKES BECOME LOCKED DURINGVEHICLE OPERATION, LOSS OF VEHICLE CONTROL AND AN ACCIDENT COULD RESULT.