NHTSA recall 79V077000
Service brakes, air › Antilock › Control unit/module
Ford B Series and 5 more
Reported Mar 29, 197965,000 vehicles affectedFORD MOTOR COMPANYBuilt Feb 1, 1975 – Mar 1, 1979
The defect
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.
The remedy
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.