United States 85V113000
Mack Trucks, Inc.
The problem
THE DUAL DOUBLE CHECK VALVE MAY NOT RELEASE THE PROPER AIR VOLUME TO THE BRAKE SYSTEM, CAUSING A SLIGHT TIMING DELAY BETWEEN THE TRACTOR AND THE TRAILER BRAKE SYSTEM. CONSEQUENCES OF DEFECT: IF THE BRAKES ARE SUDDENLY APPLIED, THE TRAILER COULD JACKKNIFE WITHOUT WARNING TO THE OPERATOR, WHICH COULD RESULT IN A VEHICLE CRASH.
What owners should do
INSTALL TWO NEW SLEEVES IN THE DUAL DOUBLE CHECK VALVE WHICH WILL INCREASE AIR FLOW.
Units 5020