THE INVOLVED TRUCKS MAY HAVE BEEN ASSEMBLED WITHOUT THE INSTALLATION OF A SINGLE CHECK VALVE. THIS FAILS TO COMPLY WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS". IN THE EVENT OF A SINGLE FAILURE IN THE REAR AIR SYSTEM, THE LACK OF A CHECK VALVE WOULD ALLOW SIMULTANEOUS LOSS OF AIR FROM BOTH FRONT AND REAR BRAKING SYSTEMS.
FixDEALER WILL INSTALL A SINGLE CHECK VALVE, IF NECESSARY, WITHOUT CHARGE TO OWNER.