MACK RS 1977: SERVICE BRAKES, AIR:SUPPLY:HOSES, LINES/PIPING, AND FITTINGS
NHTSA Campaign ID Number: 78V030000
| Make | Model | Year |
|---|---|---|
| MACK | RS | 1977 |
| Date Owners Notified | Date Received by ODI | Date Added to Database |
| 1978-08-23 | 1978-02-09 | 1979-10-12 |
Production Dates: 1975-12-01 - 1978-01-01
Manufacturers Involved: Mack Trucks, Inc.
Component: SERVICE BRAKES, AIR:SUPPLY:HOSES, LINES/PIPING, AND FITTINGS
Potential Number Of Units Affected: 400
Report Initiator: MFR MFR Report
A DESIGN DEFICIENCY EXISTS IN THE AIR DRYER PIPING IN THE AREA OF THE PRESSURE RELIEF VALVE AND COMPRESSOR GOVERNOR CONTROL LINK. MOISTURE IS PASSED AND BUILDS UP IN THIS RELIEF VALVE AND CONTROL LINE. IN FREEZING AMBIENT TEMPERATURES, THIS MOISTURE MAY FREEZE, ALLOWING THE CHASSIS AIR SYSTEM PRESSURE TO EXCEED 150 PSI. EXCESSIVE AIR SYSTEM PRESSURE CAN CAUSE SEPARATION OF AIR PIPING CONNECTIONS AND AIR SYSTEM VALVE FAILURE.
THE DEALER WILL RELOCATE THE AIR SYSTEM COMPRESSOR GOVERNOR LINE AND PRESSURE RELIEF VALVE TO ELIMINATE MOISTURE ACCUMULATION.
VEHICLE DESCRIPTION: TRUCKS EQUIPPED WITH ANCHORLOK AIR DRYERS.SYSTEM: SERVICE BRAKES; AIR SYSTEM AND GOVERNOR CONTROL LINE 'AIR DRYER'.CONSEQUENCES OF DEFECT: WHEN THIS OCCURS, AUTOMATIC APPLICATION OF THE CHASSISEMERGENCY SPRING BRAKES AND TRAILER BRAKES COULD CAUSE LOSS OF VEHICLE CONTROLWITHOUT PRIOR WARNING AND A VEHICLE ACCIDENT.NOTE: OWNER/DRIVER IS ADVISED NOT TO OPERATE VEHICLE IF AIR PRESSURE EXCEEDS15O PSI.
