United States 79V077000
Ford Motor Company
The problem
CERTAIN AIR BRAKE ANTI-LOCK MODULATORS COULD MALFUNCTION DURING OPERATION OF THE ANTI-LOCK SYSTEM. A NYLON PISTON WITHIN THE MODULATOR AIR VALVE SYSTEM CAN SWELL FROM EXPOSURE TO SYSTEM CONTAMINANTS. CONTINUED EXPOSURE MAY CAUSE THE PISTON TO SWELL TO THE EXTENT THAT INTERFERENCE WITH THE CYLINDER WALL WILL RESULT, CAUSING MOMENTARY STICKING OR A PERMANENT JAM. THIS CAN RESULT IN TEMPORARY OR PERMANENT LOSS OF BRAKING FOR THE AFFECTED AXLE.
What owners should do
THE PISTONS IN THE VALVE PORTION OF THE MODULATORS WILL BE REPLACED WITH PISTONS THAT DO NOT SWELL WHEN EXPOSED TO AIR BRAKE SYSTEM CONTAMINANTS.
Units 65000