CERTAIN HEAVY DUTY VEHICLES FAIL TO COMPLY WITH THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS." IMPROPER SEATING OF THE CHECK VALVE RETAINER IN THE BRASS FITTING HOUSING HAS OCCURRED. IT IS POSSIBLE FOR THE AIR BRAKE SYSTEM PRESSURE TO PUSH THE CHECK VALVE INTERNAL PARTS INTO THE PRIMARY SYSTEM RESERVOIR AND A VEHICLE OPERATOR WOULD NOT KNOW THAT THIS HAS HAPPENED.
RiskIN THIS CONDITION, THE VEHICLE WOULD NOT MEET THE EMERGENCY REQUIREMENTS OF THE STANDARD.
FixDEALERS WILL REPLACE THE CHECK VALVE. OWNER NOTIFICATION BEGAN NOVEMBER 26, 2003. OWNERS SHOULD CONTACT MACK AT 1-610-709-3337.