Mack WL recalls by model year

Reported: 1977-10-12 (October 12, 1977) · Model years: 1972, 1973, 1974, 1975, 1976, 1977

THE FLEX BLADE FANS ON THE INVOLVED VEHICLES MAY DEVELOP CRACKS IN THE LAMINATED STIFFENER AS A RESULT OF FATIGUE DURING OPERATION. IF SUCH A CONDITION EXISTS AND THE CRACKS GO UNDETECTED, CONTINUED OPERATION COULD CAUSE PIECES OF THE STIFFENER TO BREAK OFF.

Remedy: DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.

Reported: 1975-04-15 (April 15, 1975) · Model years: 1974

Reported: 1975-07-24 (July 24, 1975) · Model years: 1974, 1975

Reported: 1975-07-24 (July 24, 1975) · Model years: 1974, 1975

Reported: 1976-06-09 (June 9, 1976) · Model years: 1974, 1975

Reported: 1977-01-01 (January 1, 1977) · Model years: 1974, 1975, 1976

THE LOWER STEERING SHAFT YOKE CLAMP BOLTS ON THE INVOLVED VEHICLES MAY NOT HAVE BEEN SUFFICIENTLY TIGHTENED. SHOULD THESE BOLTS LOSSEN AND COME OFF, THE LOWER STEERING SHAFT COULD SEPARATE FROM THE STEERING GEAR.

Remedy: THE DEALER WILL SECURE THE CLAMP BOLT AND MAKE THE NECESSARY MODIFICATIONS ON THE LOWER STEERING SHAFT, FREE OF CHARGE.

Reported: 1978-04-04 (April 4, 1978) · Model years: 1974, 1975, 1976

AN AXLE "NO BRAKE" CONDITION COULD RESULT FROM AN EATON CONTROLLER INTERNAL ELECTRICAL MALFUNCTION. THIS CONDITION MAY CAUSE THE ANTI-WHEEL LOCK VALVE SOLENOID TO BE CONTINUOUSLY ENERGIZED AND PREVENT THE BRAKES FROM BEING APPLIED ON ONE OF THE AXLES. AS A RESULT, THE ANTI-WHEEL LOCK WARNING LAMP IS NOT ACTIVATED.

Remedy: THE DEALER WILL INSPECT AND, IF NECESSARY, REPLACE THE ANTI-WHEEL LOCK CONTROLLER WITHOUT CHARGE TO OWNER.

Reported: 1975-07-24 (July 24, 1975) · Model years: 1975

Reported: 1976-01-13 (January 13, 1976) · Model years: 1975

Reported: 1976-01-13 (January 13, 1976) · Model years: 1975

Reported: 1976-04-20 (April 20, 1976) · Model years: 1975, 1976

Reported: 1977-01-01 (January 1, 1977) · Model years: 1975, 1976

CRACKS MAY BE PRESENT IN THE BRAKE SPIDER. THESE CRACKS COULD EVENTUALLY CAUSE THE BRAKE SPIDER TO FAIL. THIS COULD ALLOW SEPARATION OF THAT PORTION OF THE BRAKE SPIDER THAT RETAINS THE BRAKE CAMSHAFT, THE BRAKE CHAMBER, AND THE BRAKE CHAMBER BRACKET FROM THE FOUNDATION BRAKE ASSEMBLY. BRAKE PULL IN THE DIRECTION OPPOSITE THE AFFECTED WHEEL LOCATION OR WHEEL LOCK-UP ON THE AFFECTED WHEEL COULD OCCUR.

Remedy: THE DEALER WILL INSPECT AND MODIFY THE AFFECTED BRAKE SPIDERS, FREE OF CHARGE.

Reported: 1978-02-09 (February 9, 1978) · Model years: 1975, 1976, 1977, 1978

A DESIGN DEFICIENCY EXISTS IN THE AIR DRYER PIPING IN THE AREA OF THE PRESSURE RELIEF VALVE AND COMPRESSOR GOVERNOR CONTROL LINK. MOISTURE IS PASSED AND BUILDS UP IN THIS RELIEF VALVE AND CONTROL LINE. IN FREEZING AMBIENT TEMPERATURES, THIS MOISTURE MAY FREEZE, ALLOWING THE CHASSIS AIR SYSTEM PRESSURE TO EXCEED 150 PSI. EXCESSIVE AIR SYSTEM PRESSURE CAN CAUSE SEPARATION OF AIR PIPING CONNECTIONS AND AIR SYSTEM VALVE FAILURE.

Remedy: THE DEALER WILL RELOCATE THE AIR SYSTEM COMPRESSOR GOVERNOR LINE AND PRESSURE RELIEF VALVE TO ELIMINATE MOISTURE ACCUMULATION.

Reported: 1978-08-08 (August 8, 1978) · Model years: 1975, 1976, 1977, 1978

THE POSSIBILITY EXISTS THAT THE ALUMINUM ENGINE REAR SUPPORT BRACKETS MAY FAIL DUE TO METAL FATIGUE. THIS TYPE OF FAILURE WOULD ALLOW THE ENGINE AND TRANSMISSION ASSEMBLY TO DISLOCATE DOWNWARD. THIS WILL RESULT IN THROTTLE CONTROL LOSS WITH THE ENGINE OPERATING CONTINUOUSLY IN THE MID TO UPPER RANGE OF THE GOVERNED SPEED RANGE.

Remedy: DEALER WILL INSPECT AND, IF NECESSARY, REPLACE ALUMINUM SUPPORT BRACKETS WITH BRACKETS MADE FROM DUCTILE IRON FOR INCREASED STRENGTH.

Reported: 1977-09-19 (September 19, 1977) · Model years: 1976, 1977

THE FRONT WHEEL ALUMINUM HUBS ON THE INVOLVED VEHICLES MAY BE SUBJECT TO CRACKS WHICH MAY PROGRESS CIRCUMFERENTIALLY AROUND THE BARREL OF THE HUB. THIS COULD LEAD TO A FRACTURE IN THE "BARREL" POSITION OF THE HUB AND COMPLETE HUB FAILURE.

Remedy: DEALER WILL INSTALL STEEL HUBS IN PLACE OF ALUMINUM HUBS WITHOUT CHARGE TO OWNER.

Reported: 1977-11-21 (November 21, 1977) · Model years: 1977

A DEFICIENCY EXISTS IN THE WELDS SECURING THE REAR SPRING INSULATOR BRACKET TO THE AXLE HOUSING. THIS IS DUE TO IMPROPER POSITIONING OF THE WELD, IN RELATIONSHIP TO THE BRACKET AND AXLE HOUSING. FAILURE OF THE WELDS WOULD CAUSE SEPARATION OF THE SPRING INSULATOR BRACKET AND THE AXLE HOUSING, RESULTING IN IMPROPER ALIGNMENT OF THE AFFECTED AXLE.

Remedy: DEALER WILL REWELD THE INSULATOR SPRING BRACKET AT NO COST TO OWNER.

Reported: 1978-10-03 (October 3, 1978) · Model years: 1977, 1978

DELAYS OF UP TO ABOUT 2 SECONDS MAY EXIST IN THE BRAKE APPLICATION TIMES TO THE BRAKES ON THE BOGIE AXLES IN THE PRESENCE OF CERTAIN TYPES OF WHEEL SPEED SENSOR SIGNAL DISCONTINUITIES OR DISTORTIONS THAT MAY OCCUR AS A RESULT OF SENSOR WIRE FAILURE. THIS CONSTITUTES A NON-COMPLIANCE TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS".

Remedy: DEALER WILL INSTALL NEW WHEEL SPEED SENSORS THAT INCORPORATE IMPROVED WIRING AND THE PRESENT BOGIE ANTI-WHEEL LOCK SYSTEM WILL BE CHANGED TO AN AXLE-TO-AXLE SYSTEM FOR IMPROVED RELIABILITY.

Reported: 1979-05-31 (May 31, 1979) · Model years: 1977, 1978, 1979

IN THE EVENT OF TURBOCHARGER COMPRESSOR WHEEL FAILURE, ONE OR MORE OF THE FOUR CAPSCREWS THAT HOLD THE TURBOCHARGER TOGETHER MAY BE STRUCK BY PARTS OF THE COMPRESSOR WHEEL, RESULTING IN THE CAPSCREWS BEING DAMAGED. IF THESE CAPSCREWS ARE DAMAGED TO THE POINT THAT THEY ALLOW THE COMPRESSOR BACK PLATE TO DISLOCATE FROM THE TURBOCHARGER BEARING HOUSING, ENGINE LUBRICATING OIL MAY BE ALLOWED TO ESCAPE UNDER PRESSURE, CONTACTING THE ENGINE EXHAUST MANIFOLD SECTIONS OR TURBOCHARGER TURBINE HOUSING.

Remedy: DEALER WILL INSTALL A SHIELD FOR THE HEADS OF THE FOUR CAPSCREWS, ALONG WITH STRONGER SAE 8 GRADE 8 CAPSCREWS, IF NECESSARY, AT NO COST TO OWNER.

Reported: 1979-06-01 (June 1, 1979) · Model years: 1977, 1978, 1979

THE PITMAN ARM RETAINING NUT MAY NOT HAVE BEEN TORQUED TO MANUFACTURER SPECIFICATIONS. THIS COULD RESULT IN INADEQUATE RETENTION OF THE NUT AT THE OUTPUT SHAFT, ALLOWING THE PITMAN ARM TO BECOME LOOSE.

Remedy: DEALER WILL INSPECT AND RETORQUE PITMAN ARM, IF NECESSARY, AT NO COST TO OWNER.

Reported: 1979-07-09 (July 9, 1979) · Model years: 1979

THE FLANGE HEAD PINCH BOLTS USED IN THE YOKES OF THE STEERING SHAFT ASSEMBLIES MAY HAVE BEEN OVERSTRESSED DUE TO THE BOLTS NOT BEING TIGHTENED TO SPECIFICATIONS. AS A RESULT, THE PINCH BOLTS COULD BREAK WHILE IN SERVICE.

Remedy: FLANGE HEAD PINCH BOLTS WILL BE REPLACED WITH STANDARD GRADE 8 FASTENERS WITHOUT CHARGE TO OWNER.

Reported: 1979-07-12 (July 12, 1979) · Model years: 1979

THE SPRING SEAT PLATE, LOCATED BETWEEN THE AXLE HOUSING AND THE SUSPENSION SPRINGS, MAY DEFORM DUE TO SPRING BENDING. AS A RESULT, THE CLAMPING FORCE IN THE ASSEMBLY MAY BE REDUCED. LOSS OF CLAMPING FORCE COULD CAUSE SPRING FAILURE AND THE AXLE WILL DISLOCATE. ALSO, THE TIRE COULD COME INTO CONTACT WITH THE SPRING.

Remedy: THE DEALER WILL REPLACE THE EXISTING SPRING SEAT WITH A NEWLY FABRICATED SEAT WHICH IS WELDED TO THE HOUSING. AN IMPROVED SPRING CLAMPING PLATE AND NEW SPRINGS WILL ALSO BE INSTALLED WITHOUT CHARGE.

Reported: 1983-04-14 (April 14, 1983) · Model years: 1980, 1981

THE PITMAN ARM, A LEVER THAT TRANSMITS TURNING MOVEMENTS FROM THE STEERING GEAR TO THE STEERING LINKAGE, MAY LOOSEN OR BREAK AT ITS CONNECTION TO THE STEERING LINKAGE. THE FAILURE CAN PREVENT TURNING ATTEMPTS FROM HAVING ANY EFFECT. THE DEFECT IS CAUSED BY INCORRECT ASSEMBLY OF THE BALL STUD CONNECTION IN THE PITMAN ARM.

Remedy: THE DEALER WILL INSTALL A NEW PITMAN ARM BALL ASSEMBLY AT NO CHARGE.