PARKING BRAKE:DRIVELINE:HYDRAULIC:HOSES, LINES/PIPING, AND FITTINGS
Nov 26, 1985
3,308 units potentially affected
The defect: THE QUICK RELEASE VALVE SUPPORT BRACKET MOUNTED ON THE AXLE MAY CRACK. THIS CAUSES FATIGUE FAILURE OF THE STEEL AIR LINES LEADING TO THE REAR PARKING BRAKES AND CHASSIS SERVICE BRAKES RESULTING IN SUDDEN LOSS OF AIR PRESSURE. CONSEQUENCE OF DEFECT: THIS SUDDEN LOSS OF AIR TO THE BRAKE CHAMBERS WILL RESULT IN AUTOMATIC ACTUATION OF REAR PARKING BRAKE CAUSING SUDDEN REAR WHEEL LOCKUP WHICH MAY CONTRIBUTE TO AN ACCIDENT.
The remedy: INSTALL A REDESIGNED VALVE SUPPORT BRACKET.
MACK TRUCKS, INCORPORATEDView on NHTSA.gov