Defect summary
SECONDARY SERVICE RESERVOIR AIR CHECK VALVES MAY NOT SEAT PROPERLY DUE TO A MECHANICAL INTERFERENCE CONDITION BETWEEN A CIRCULAR BRASS GUIDE AND THE WALL OF A CYLINDRICAL FERRULE IN WHICH THE BRASS GUIDE IS INTENDED TO MOVE FREELY.
Consequence
IN THE EVENT OF PRESSURE LOSS IN THE SUPPLY RESERVOIR,A DEFECTIVE CHECK VALVE WOULD ALLOW PRESSURE EQUALIZATION BETWEEN PRIMARY ANDSECONDARY SERVICE RESERVOIRS, PRESENTING THE POTENTIAL FOR LOSS OR ABSENCE OFFRONT BRAKING ABILITY, WHICH COULD CAUSE LOSS OF CONTROL AND AN ACCIDENT.
Remedy
INSTALL REVISED DESIGN SECONDARY SERVICE RESERVOIR CHECK VALVE COMPONENTS.
Notes
SYSTEM: AIR PRESSURE CHECK VALVES.VEHICLE DESCRIPTION: HEAVY DUTY TRUCKS AND CHASSIS CABS.
Source: NHTSA ODI recalls file, campaign 90V121000. Text as published by NHTSA.