Service brakes, air: supplyRecall 77V-186 · Motor Coach vehicles
MOTOR COACH IND., INC. recall 77V-186 covers 1,182 Motor Coach vehicles for a service brakes, air: supply problem, reported to NHTSA on October 25, 1977.
Source: NHTSA recall 77V186000 and manufacturer quarterly reports. Started by the manufacturer.
The problem
THE INVOLVED VEHICLES DO NOT CONFORM TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS". THE TWO "O" RINGS THAT ARE SUPPLIED ALONG WITH THE NEW SHUTTLE VALVES ARE OF A BUNA "V" QUALITY. THESE RINGS ARE FULLY FUNCTIONAL IN NORMAL CLIMATE CONDITIONS, HOWEVER, IN EXTREMELY COLD ENVIRONMENTS, SLIGHT LEAKS MAY DEVELOP. THIS VALVE ACTS AS A SEAL BETWEEN THE CYLINDER HEADS OF THE SHUTTLE VALVE AND THE PISTON. IN TIME THIS SEAL MAY EXPAND OR "PUCKER UP", MAKING IT POSSIBLE FOR THE SHUTTLE TO BECOME TRAPPED IN AN EMERGENCY BRAKING SITUATION.
The fix
THE DEALER WILL REPLACE ALL DEFECTIVE "O" RINGS WITH ONES HAVING EXTREME COLD RESISTANCE PROPERTIES.
VEHICLE DESCRIPTION: MOTOR HOMES EQUIPPED WITH NEW SHUTTLE VALVES.SYSTEM: SERVICE BRAKES; AIR CONTROL VALVE.CONSEQUENCES OF DEFECT: IN THIS EVENT, THE BRAKES ONCE "ON" WILL NOT RELEASEAND LOSS OF VEHICLE CONTROL AND AN ACCIDENT COULD RESULT.NOTE: DRIVER SHOULD BE ALERTED TO THIS CONDITION BY A FLASHING LIGHT, BUZZER,AND A LOW READING ON THE AIR GAUGE.
Recall repairs are free. Confirm whether this recall is open on your vehicle by entering its VIN at nhtsa.gov/recalls.