NHTSA recall 78V008000
Service brakes, air › Supply
Tmc MC8
Reported Jan 16, 1978527 vehicles affectedTRANSIT MANUFACTURING,INCBuilt Aug 1, 1976 – Oct 1, 1977
The defect
The involved vehicles may not comply with federal motor vehicle safety standard no. 121, "modulated emergency braking". The "o" rings in the shuttle valve may develop slight leaks in cold weather. In addition, neoprene washers used on these "o" rings may eventually expand or pucker in cold climates, making it possible for the shuttle piston to become trapped by the inner-circumferences of the washers. This would force the emergency brakes to the "on" position and would prevent them from being released.
The remedy
The dealer will replace the two neoprene washers with glass filled teflon washers that will not be affected by cold climates.