1977 Motor Coach Mc5b Recalls

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NHTSA Campaign Number: 77V186000
Manufacturer: Motor Coach Industries
Date of Owner Notification: October 5th, 1977

Defect Summary:
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.

Corrective Summary:
THE DEALER WILL REPLACE ALL DEFECTIVE "O" RINGS WITH ONES HAVING EXTREME COLD RESISTANCE PROPERTIES.

Recall Notes:
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.

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NHTSA Campaign Number: 79V178000
Manufacturer: Motor Coach Industries
Manufactured Begin Date: February 1st, 1975
Manufactured End Date: September 1st, 1977
Date of Owner Notification: October 1st, 1979

Defect Summary:
CERTAIN VEHICLES DO NOT COMPLY TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS". THE LOW AIR WARNING SIGNAL MAY NOT ACTIVATE UNTIL SERVICE RESERVOIR PRESSURE IS BELOW 60 PSI. ALSO, THE BRAKE RELEASE TIME MAY EXCEED THE REQUIRED 0.55 SECONDS ON THE RIGHT HAND FRONT WHEEL.

Corrective Summary:
DEALER WILL ADJUST THE PIN SWITCH TO PRESSURE TO BRING VEHICLES INTO COMPLIANCE WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121.

Recall Notes:
VEHICLE DESCRIPTION: BUSES, INTERCITY.SYSTEM: SERVICE BRAKES; LOW AIR WARNING SIGNAL.CONSEQUENCES OF DEFECT: AIR PRESSURE MAY FALL TOO LOW AND VEHICLE OPERATORWOULD NOT BE WARNED. RESULTING PARTIAL LOSS OF BRAKING CAPABILITY COULD CAUSE AVEHICLE ACCIDENT.