Mack MH recalls by model year

Reported: 1983-09-27 (September 27, 1983) · Model years: 1982, 1983

UNDER SEVERE STRAIN, A DEFECTIVE WELD JOINING THE STEERING WHEEL HUB TO THE HUB PERIMETER COULD FAIL, CAUSING THE STEERING WHEEL TO SEPARATE FROM THE VEHICLE.

Remedy: DEFECTIVE STEERING WHEELS WILL BE REPLACED AT NO CHARGE TO OWNER.

Reported: 1984-03-23 (March 23, 1984) · Model years: 1982, 1983

A MANUFACTURING ERROR RESULTED IN THE INSTALLATION OF CARBON STEEL SPRINGS IN SOME DUAL-COMPARTMENT AIR RESERVOIR CHECK VALVES. CARBON STEEL SPRINGS ARE INADEQUATE FOR THIS APPLICATION BECAUSE THEY ARE SUBJECT TO SEVERE CORROSION AND SUBSEQUENT FAILURE OF THE CHECK VALVE.

Remedy: THE CARBON STEEL SPRING WILL BE REPLACED WITH A STAINLESS STEEL ONE.

Reported: 1984-11-07 (November 7, 1984) · Model years: 1982, 1983, 1984

DUE TO IMPROPER AND INADEQUATE WELDING PRACTICES, THE FIFTH WHEEL ON THE INVOLVED VEHICLES IS DEFECTIVE. FRAME MOUNTED SUPPORTS MAY HAVE INCOMPLETE OR POOR QUALITY WELDS. THE WELDS COULD SUBSEQUENTLY FAIL ALLOWING SEPARATION OF THE TRACTOR FROM THE TRAILER.

Remedy: THE DEALER WILL INSPECT AND REMOVE THE FIFTH WHEEL AND REWELD THE MOUNTING ANGLES AT NO CHARGE TO THE OWNER.

Reported: 1985-05-01 (May 1, 1985) · Model years: 1982, 1983, 1984, 1985

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.

Remedy: REMOVE THE STEP CLEVIS AND REPLACE WITH A NEW IMPROVED CLEVIS.

Reported: 1985-09-17 (September 17, 1985) · Model years: 1982, 1983, 1984, 1985

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.

Remedy: INSTALL TWO NEW SLEEVES IN THE DUAL DOUBLE CHECK VALVE WHICH WILL INCREASE AIR FLOW.

Reported: 1986-01-17 (January 17, 1986) · Model years: 1982, 1983, 1984, 1985, 1986

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.

Remedy: INSTALL A REINFORCEMENT BRACE IF NO CRACKS ARE FOUND. IN ADDITION, REPLACE STEP IF CRACKS ARE PRESENT.

Reported: 1988-09-06 (September 6, 1988) · Model years: 1982, 1983, 1984, 1985, 1986, 1987, 1988

SEAT TETHER BELTS MAY NOT HAVE BEEN ADJUSTED DURING ASSEMBLY.

Consequence: DURING AN IMPACT, DRIVER AND/OR RIDER CAN MOVE FORWARDAND POSSIBLY STRIKE THE WINDSHIELD, EVEN WHEN WEARING A SEAT BELT.

Remedy: ADJUST SEAT TETHER BELT IF NECESSARY.

Reported: 1984-03-22 (March 22, 1984) · Model years: 1983, 1984

IMPROPER STEERING CLAMP BOLTS AND TORQUE APPLIED DURING INSTALLATION. THE BOLT COULD FAIL, ALLOWING THE STEERING YOKE TO BECOME LOOSE.

Remedy: INSPECTION AND, IF NECESSARY, INSTALLATION OF PROPER STEERING SHAFT CLAMP BOLTS TIGHTENED TO SPECIFICATIONS.

Reported: 1984-11-07 (November 7, 1984) · Model years: 1984

THE DOOR LATCHES MAY BE DEFECTIVE BECAUSE A PAWL SPRING WAS NOT MANUFACTURED TO SPECIFICATIONS. THE PAWL SPRING DOES NOT CREATE PROPER TENSION ON THE PAWL, (A PART OF THE DOOR LATCH MECHANISM). THIS CONSTITUTES A NON-COMPLIANCE WITH THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 206, "DOOR LATCHES AND DOOR RETENTION COMPONENTS".

Remedy: THE DEALER WILL INSPECT AND REPLACE DOOR LATCHES, IF NECESSARY.

Reported: 1984-11-07 (November 7, 1984) · Model years: 1984

THE SPRING CENTER BOLT IS NOT THE PROPER SIZE OR LENGTH. AS A RESULT, LOCATION AND ALIGNMENT OF THE SPRING TO THE FRONT AXLE MAY NOT BE CORRECT. IF THE FRONT SPRING CLIPS LOOSEN, THE INADEQUATE CENTER BOLT MAY RESULT IN SPRING TO AXLE MISALIGNMENT, SHIFTING OF THE AXLE, AND LOSS OF STEERING CONTROL.

Remedy: THE DEFECT WILL BE CORRECTED BY THE ADDITION OF A SPACER BETWEEN THE SPRING AND THE CENTER BOLT HEAD TO INCREASE THE EFFECTIVE HEAD LENGTH. A LONGER CENTER BOLT WILL ALSO BE INSTALLED FOR POSITIVE RETENTION.

Reported: 1985-05-03 (May 3, 1985) · Model years: 1984, 1985

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.

Remedy: ASSURE THAT DRAG LINKS ARE INSTALLED TO CORRECT INTERFERENCE CONDITION.

Reported: 1987-10-26 (October 26, 1987) · Model years: 1986, 1987

ON RIGHT HAND STEERING ARM, KEYWAY MAY BE IN THE WRONG LOCATION CAUSING A TOGGLE CONDITION TO OCCUR UNDER CERTAIN CONDITIONS.

Consequence: THIS COULD RESULT IN SLOW STEERING RETURN WITHOUT PRIORWARNING WHICH WOULD AFFECT STEERING CONTROL AND CREATE THE POTENTIAL FOR ACRASH.

Remedy: REPLACE INCORRECT STEERING ARM.

Reported: 1987-11-23 (November 23, 1987) · Model years: 1987

CROSS STEERING LEVERS MAY BE IMPROPERLY HEAT TREATED AND SUBJECT TO FAIL DURING NORMAL OPERATION.

Consequence: SUCH FAILURE COULD CAUSE LOSS OF TRUCK CONTROL WITHOUTPRIOR WARNING AND RESULT IN A CRASH.

Remedy: INSTALL NEW, PROPERLY HEAT TREATED STEERING LEVER.

Reported: 1987-12-14 (December 14, 1987) · Model years: 1987

THE PITMAN ARM TO DRAG LINK ANGLE IS OUT OF PHASE.

Consequence: UNDER CERTAIN CONDITIONS, STEERING LINKAGE COULD GO INTOA TOGGLE CONDITION RESULTING IN A SLOW WHEEL RETURN AND IMPAIRED STEERINGCONTROL, CREATING THE POTENTIAL FOR A VEHICLE CRASH WITHOUT PRIOR WARNING.

Remedy: REPLACE MISMARKED PITMAN ARM.

Reported: 1989-02-21 (February 21, 1989) · Model years: 1987, 1988

SEAT TETHER BELT 11.0 INCHES LONG WAS INSTALLED INSTEAD OF THE 8.5 INCHES LONG BELT REQUIRED FOR THIS CHASSIS.

Consequence: INCORRECT LENGTH BELT MAY NOT PROPERLY RESTRAIN OCCUPANTAND WOULD NOT COMPLY WITH FMVSS 210.

Remedy: INSTALL CORRECT 8.5 INCH SEAT TETHER BELT.

Reported: 1994-02-15 (February 15, 1994) · Model years: 1987, 1988, 1989, 1990, 1991, 1992

FUEL INJECTION SYSTEM RECONFIGURATION TO COMPLY WITH ENGINE EMISSION STANDARDS CAUSE HIGHER ENGINE VIBRATION LEVELS WHICH LEAD TO EARLY WEAR AND COMPLETE FAILURE OF THE SECONDARY THROTTLE RETURN MECHANISM.

Consequence: IN THE EVENT THE PRIMARY THROTTLE RETURN FAILS, FAILURE OF THE SECONDARY THROTTLE RETURN SYSTEM WOULD NOT PROVIDE PROTECTION AGAINST LOSS OF THROTTLE CONTROL.

Remedy: A NEW PRODUCTION SECONDARY THROTTLE RETURN SYSTEM CONFIGURATION WILL BE INSTALLED.

Reported: 1989-03-03 (March 3, 1989) · Model years: 1988

DOWELS MAY HAVE BEEN OMITTED DURING SPRING CAP INSTALLATION; THIS WOULD PUT SHEAR LOAD ON THE FOUR (4) SPRING CAP BOLTS.

Consequence: THIS COULD RESULT IN LOOSENING AND FAILURE OF THE BOLTSWITH POSSIBLE LOSS OF CONTROL AND ACCIDENT POTENTIAL.

Remedy: INSTALL THE MISSING DOWELS TO PREVENT MOVEMENT BETWEEN THE SPRING CAP AND AXLE HOUSING.

Reported: 1989-05-15 (May 15, 1989) · Model years: 1989

TORQUE ROD BOLTS ARE GRADE 2 INSTEAD OF GRADE 5, WHICH IS NOT TO SPECIFICATION, AND COULD FAIL.

Consequence: BOLT FAILURE COULD ALLOW THE REAR AXLE TO SHIFT; THISCOULD ADVERSELY AFFECT TRUCK CONTROL AND COULD RESULT IN A CRASH.

Remedy: REPLACE TORQUE ROD BOLTS WITH BOLTS OF THE PROPER SPECIFICATION.

Reported: 1993-02-16 (February 16, 1993) · Model years: 1992, 1993

THE CARRIER YOKE BOLTS WERE MANUFACTURED WITH WORN ROLLING THREAD DIES, CAUSING STRESS CONCENTRATIONS WHICH CAUSED CRACKS DURING THE QUENCHING PROCESS.

Consequence: THIS CONDITION CAN CAUSE BOLT FAILURE AND ALLOW THEDRIVELINE TO SEPARATE FROM THE CARRIER ASSEMBLY.

Remedy: REPLACE THE CARRIER YOKE BOLTS.