Mack Trucks, Inc.: Safety Recalls in 1986

STEERING COLUMN BOOT ATTACHED TO EXTERIOR OF FIREWALL COULD BE DEFORMED BY THE SOUND INSULATION PLACED ON THE FIREWALL AND CAUSES INTERFERENCE WITH THE STEERING SHAFT U-JOINT BOLT. CONSEQUENCE OF DEFECT: AN IMPROPERLY FITTED OR DEFORMED BOOT COULD GET CAUGHT ON BOLT WHICH RETAINS THE STEERING U-JOINT AND RESULT IN SUDDEN HARD STEERING, POSSIBLE LOSS OF CONTROL AND A POTENTIAL CRASH.

THE DRAG LINK TO PITMAN ARM TOGGLE ANGLE MAY BE GREATER THAN DESIGN CRITERIA, AND MAY CAUSE THE STEERING TO BIND. CONSEQUENCE OF DEFECT: IF TRUCK NEGOTIATES EXTREME RIGHT HAND TURN THE LEFT FRONT WHEEL DROPS INTO A DEEP HOLE, STEERING RETURN WOULD BE SLOW, WITHOUT WARNING TO OPERATOR, CREATING POTENTIAL FOR A VEHICLE CRASH.

AN INCORRECT STEERING SHAFT RETAINING NUT IS INSTALLED ON THE SHAFT AND CAN LOOSEN CAUSING STEERING PLAY. CONSEQUENCE OF DEFECTS: IF NUT IS NOT REPLACED, STEERING WHEEL DISENGAGEMENT COULD OCCUR CAUSING LOSS OF STEERING CONTROL AND POSSIBLY A VEHICLE CRASH.

THE SEALANT USED ON THE INJECTION PUMP COULD PENETRATE THROUGH THE BUSHING AND GET BETWEEN THE THROTTLE SHAFT AND BUSHINGS CAUSING THE SHAFT TO BIND. CONSEQUENCE OF DEFECT: THROTTLE SHAFT SEIZURE MAY CAUSE THE ENGINE TO STAY ON FULL THROTTLE, AND RESULT IN LOSS OF OPERATOR CONTROL AND POSSIBLY AN ACCIDENT.

FRONT STEERING KNUCKLE THRUST BEARING MAY SHATTER INTO PIECES DUE TO IMPROPER HEAT TREATMENT. CONSEQUENCE OF DEFECT: FAILURE OF THE BEARING MAY AFFECT STEERING CONTROL. IF BEARING DISINTEGRATES, IT WOULD RESULT IN INCREASE STEERING DRAG AND/OR CAUSE STEERING LOCK UP WITH LOSS OF CONTROL WHICH COULD LEAD TO AN ACCIDENT.

THE SPRING EYE BOLT WAS NOT TORQUED PROPERLY AND COULD FAIL DUE TO THE LOOSE FIT WITHIN THE SPRING EYE BUSHING/HANGER BRACKET. CONSEQUENCE OF DEFECT: THE SPRING COULD FALL ONTO THE ROAD SURFACE, WITHOUT WARNING TO THE DRIVER, AND A VEHICLE CRASH COULD OCCUR DUE TO THE SUDDEN DRAG OF THE SPRING.

THE ACCELERATOR ROD HOLE CLEARANCE IS NOT ADEQUATE AND CAN CAUSE THE ACCELERATOR LINKAGE TO BIND. CONSEQUENCE OF DEFECT: IF BINDING OCCURS WHILE IN A FULL THROTTLE POSITION, ACCELERATOR CONTROL WOULD BE LOST WITHOUT WARNING AND AN ACCIDENT COULD OCCUR.

LEFT OR RIGHT CAB STEP MAY CRACK IN ITS WELDED AREA DUE TO FLEXING OF THE STEP DURING ENTERING AND EXITING. CONSEQUENCE OF DEFECT: AS THE CRACKS EXTEND, THE TUBULAR STEP COULD PARTIALLY COLLAPSE AND BREAK WITHOUT WARNING TO THE USER, AND COULD RESULT IN PERSONAL INJURIES.

INCORRECT INNER WHEEL BEARINGS WERE INSTALLED IN THE REAR AXLES WHICH WEARS A GROOVE IN THE SPINDLE DUE TO A POOR FIT. CONSEQUENCE OF DEFECT: A DEEP GROOVE COULD CAUSE THE AXLE HOUSING TO BREAK AND RESULT IN A VEHICLE CRASH WITHOUT PRIOR WARNING.