United States 85V159000
Mack Trucks, Inc.
The problem
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.
What owners should do
INSTALL A REDESIGNED VALVE SUPPORT BRACKET.
Units 3308