The defect
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 remedy
THE DEALER WILL REPLACE ALL DEFECTIVE "O" RINGS WITH ONES HAVING EXTREME COLD RESISTANCE PROPERTIES.
NHTSA's own wording · initiated by MFR
Vehicles covered
| Model | Model years |
|---|
Components: SERVICE BRAKES, AIR:SUPPLY
Other service brakes, air recalls in 1977
19 of the 245 recall campaigns reported to NHTSA in 1977 concerned the service brakes, air; MOTOR COACH IND., INC. filed 35 campaigns in all.
| 77V224000 15 Dec 1977 | WHITE MOTOR CORPORATION |
| 77V206000 21 Nov 1977 | WHITE MOTOR CORPORATION |
| 77V177000 14 Oct 1977 | INTERNATIONAL HARVESTER |
| 77V156000 21 Sept 1977 | GREAT DANE TRAILERS, INC. |
| 77V153000 20 Sept 1977 | GREAT DANE TRAILERS, INC. |
| 77V148000 19 Sept 1977 | TRAILMOBILE INC. |
| 77V147000 19 Sept 1977 | PACCAR, INCORPORATED |
| 77V145000 15 Sept 1977 | GENERAL MOTORS CORP. |
NHTSA recalls (public domain) · all recalls of 1977