Mack Trucks, Inc.: Safety Recalls in 1985

THE QUICK RELEASE VALVE SUPPORT BRACKET MOUNTED ON THE AXLE MAY CRACK. THIS CAUSES FATIGUE FAILURE OF THE STEEL AIR LINES LEADING TO THE REAR PARKING BRAKES AND CHASSIS SERVICE BRAKES RESULTING IN SUDDEN LOSS OF AIR PRESSURE. CONSEQUENCE OF DEFECT: THIS SUDDEN LOSS OF AIR TO THE BRAKE CHAMBERS WILL RESULT IN AUTOMATIC ACTUATION OF REAR PARKING BRAKE CAUSING SUDDEN REAR WHEEL LOCKUP WHICH MAY CONTRIBUTE TO AN ACCIDENT.

THE SPLINED STEERING SHAFT MAY NOT BE SUFFICIENTLY ENGAGED AS DESIGNED DUE TO INACCURATE DRILLING OF THE HOLES IN THE FRAME TO WHICH THE CAB FRONT MOUNT MEMBER IS BOLTED. UNDER CERTAIN CONDITIONS THE STEERING SHAFT MAY DISENGAGE. CONSEQUENCE OF DEFECT: A JARRING IMPACT MIGHT CAUSE DISENGAMENT OF THE SPLINED SHAFT RESULTING IN LOSS OF STEERING CONTROL AND POSSIBLY AN ACCIDENT.

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.

THE DRAG LINKS MAY HAVE BEEN INSTALLED INCORRECTLY ALLOWING DRAG LINK CLAMP BOLT TO AXLE BEAM INTERFERENCE. CONSEQUENCE OF DEFECT: DURING A TURNING MANEUVER, INCREASED STEERING EFFORT OR COMPLETE LOCKUP OF STEERING COULD OCCUR WITHOUT WARNING. THIS COULD RESULT IN LOSS OF TRUCK CONTROL AND A CRASH.

THE FLIP OUT STEP CLEVIS ON THE BUMPER MAY FAIL AND BREAK UNDER THE WEIGHT OF THE PERSON STANDING ON THE STEP TO SERVICE THE FRONT AREA OF THE VEHICLE. CONSEQUENCE OF DEFECT: THIS SUDDEN BREAK WILL CAUSE THE PERSON STANDING ON THE STEP TO FALL, WITHOUT WARNING, AND COULD RESULT IN INJURIES.