Mack · Canada · Mod
Mack RS, WL +2 more: Not Entered
Affects Mack RS, WL, RL, WS · 1974–1975 — about 125 vehicles.
The hazard
THE TRAILER SUPPLY CONTROL VALVE EXHAUST PORT MAY HAVE INADVERTENTLY PLUGGED AND THE SAFETY VALVE ON THE AIR RESERVOIR MAY HAVE BEEN OMITTED. IF THE TRAILER SUPPLY CONTROL VALVE EXHAUST PORT IS PLUGGED, IT COULD CAUSE INTERMITTENT LOCK-UP OF THE TRAILER BRAKES AND OCCASIONAL DIFFICULTY IN CHARGING THE TRAILER BRAKE AIR SYSTEM. OMISSION OF THE AIR RESERVOIR SAFETY VALVE COULD RESULT IN EXCESSIVE AIR BRAKE SYSTEM PRESSURES IN THE EVENT OF A MALFUNCTION OF THE AIR COMPRESSOR GOVERNOR. CONTINUED VEHICLE OPERATION WITH EXCESSIVE PRESSURE COULD LEAD TO SYSTEM FAILURE.
What to do
Contact your dealer; the remedy details were not included in the filing.
Critical — crash/injury risk now
High — injury risk; see remedy
Moderate — fix at next service
Low — minor / informational