1974 Mack Dm Recalls

---

NHTSA Campaign Number: 79V134000
Manufacturer: Mack Trucks, Inc.
Manufactured Begin Date: June 1st, 1974
Manufactured End Date: March 1st, 1978
Date of Owner Notification: November 10th, 1979

Defect Summary:
IN THE INVOLVED TRUCKS IT IS POSSIBLE THE ADJUSTABLE STEERING COLUMN REAR MOUNTING BRACKET COULD FAIL, ALLOWING STEERING WHEEL ASSEMBLY TO FALL DOWN ONTO THE OPERATOR"S LAP.

Corrective Summary:
DEALER WILL INSTALL AN ADDITIONAL BRACKET IN THIS AREA TO PREVENT THE STEERING WHEEL FROM DISLOCATING IN THE EVENT OF A BRACKET FAILURE.

Recall Notes:
VEHICLE DESCRIPTION: TRUCKS.SYSTEM: STEERING ASSEMBLY; STEERING WHEEL AND COLUMN.CONSEQUENCES OF DEFECT: WHILE STEERING WOULD REMAIN FUNCTIONAL IN THISCONDITION, THE ELEMENT OF SURPRISE TO OPERATOR COULD CAUSE LOSS OF VEHICLECONTROL AND AN ACCIDENT.

---

NHTSA Campaign Number: 78V068000
Manufacturer: Mack Trucks, Inc.
Manufactured Begin Date: October 1st, 1974
Manufactured End Date: March 1st, 1976
Date of Owner Notification: September 1st, 1978

Defect Summary:
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.

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

Recall Notes:
VEHICLE DESCRIPTION: TRUCKS EQUIPPED WITH EATON 21 ANTI-LOCK CONTROLLERS.SYSTEM: SERVICE BRAKES; ANTI-WHEEL LOCK SOLENOID.CONSEQUENCES OF DEFECT: LOSS OF BRAKES ON ANY ONE AXLE WILL RESULT IN EXTENDEDVEHICLE STOPPING DISTANCES, WHICH COULD LEAD TO A VEHICLE ACCIDENT.

---

NHTSA Campaign Number: 78V172000
Manufacturer: Mack Trucks, Inc.
Date of Owner Notification: February 22nd, 1979

Defect Summary:
THE EXISTING CROSS STEERING ARMS MAY HAVE INSUFFICIENT FATIGUE LIFE IN THE NECK AREA. THIS IS NEAR THE BOSS FOR THE CROSS STEERING TUBE BALL JOINT CONNECTION. FAILURE OF EITHER OF THE CROSS STEERING LEVERS COULD LEAD TO LOSS OF STEERING CONTROL OF THE RIGHT FRONT WHEEL.

Corrective Summary:
THE DEALER WILL INSPECT AND, IF NECESSARY, INSTALL CROSS STEERING ARMS OF IMPROVED DESIGN AND GREATER STRENGTH.

Recall Notes:
VEHICLE DESCRIPTION: TRUCK TRACTORS.SYSTEM: STEERING; STEERING ARM.CONSEQUENCES OF DEFECT: LOSS OF STEERING CONTROL COULD LEAD TO LOSS OF VEHICLECONTROL AND AN ACCIDENT.

---

NHTSA Campaign Number: 77V173000
Manufacturer: Mack Trucks, Inc.
Date of Owner Notification: March 23rd, 1978

Defect Summary:
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.

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

Recall Notes:
VEHICLE DESCRIPTION: TRUCKS EQUIPPED WITH SIX-CYLINDER ENGINES.SYSTEM: ENGINE COOLING; FAN.CONSEQUENCES OF DEFECT: BROKEN PIECES CAN BE PROPELLED OUTSIDE OF THE FANSHROUD AND WILL PRESENT AN IMMEDIATE DANGER AND POSSIBLE INJURY TO PERSONSSTANDING NEARBY.NOTE: PRIOR TO CORRECTION, VEHICLE SHOULD NOT BE SERVICED WITH THE HOOD RAISEDAND THE ENGINE RUNNING.

---

NHTSA Campaign Number: 75V190000
Manufacturer: Mack Trucks, Inc.
Date of Owner Notification: February 23rd, 1976

Recall Notes:
MACK CAMPAIGN NO Q1010.TRUCKS SEPT.1974 THRU JULY 17, 1975.POSSIBILITYTHAT THE POWER AND WARNING LIGHT LEAD FROM THE ANTI-WHEEL LOCK CONTROLLER FORTHE STEERING AXLE MAY HAVE BEEN INADVERTENTLY CONNECTED INCORRECTLY TO A WHEELSENSOR CABLE.IF THIS OCCURS,THE CONTROLLER ON THE STEERING AXLE WOULD NOT BEPOWERED NOR WOULD THE ANTI-WHEEL LOCK WARNING LIGHT INDICATE THENON-FUNCTIONING CONDITION TO THE DRIVER.THE ABSENCE OF ANTI-WHEEL LOCKCAPABILITY ON THE STEERING AXLE, ALONG WITH THE ABSENCE OF ANTI-WHEEL LOCKWARNING LIGHT INDICATION, COULD RESULT IN IMPAIRED VEHICLE CONTROL, SHOULD THEDRIVER UNDERTAKE A PANIC STOP IN SLIPPERY ROAD CONDITIONS.(CORRECT BYINSPECTING AND PROPERLY CONNECT WIRING TO ANTI-WHEEL LOCK CONTROLLER).

---

NHTSA Campaign Number: 75V192000
Manufacturer: Mack Trucks, Inc.
Date of Owner Notification: February 20th, 1976

Recall Notes:
MACK CAMPAIGN NO N/A.TRUCKS WITH DUAL BRAKE TREADLE VALVE PIPING SEPT.1974AND MAR.31, 1975.POSSIBILITY THAT THE PRIMARY AND SECONDARY AIR SUPPLYLINES MAY HAVE BEEN CONNECTED IN REVERSE AT THE DUAL BRAKE TREADLE VALVE.THEREVERSING OF THESE SUPPLY LINES DOES NOT IN ITSELF, AFFECT VEHICLE BRAKING IFBOTH THE PRIMARY AND SECONDARY AIR SUPPLY SYSTEMS HAVE NORMAL OPERATING AIRPRESSURE.HOWEVER, IN THE EVENT OF LOSS OF AIR PRESSURE IN EITHER THE PRIMARYOR SECONDARY SYSTEM, NEITHER THE PRIMARY NOR SECONDARY SERVICE BRAKES WOULDFUNCTION WHEN APPLIED.IN THIS EVENT, IT WOULD REQUIRE MANUAL APPLICATION OFTHE EMERGENCY SPRING BRAKE TO STOP VEHICLE.(CORRECT BY INSPECTING ANDREROUTING AIR SUPPLY PIPING AS REQUIRED TO CORRECT SYSTEM).

---

NHTSA Campaign Number: 74V227000
Manufacturer: Mack Trucks, Inc.
Date of Owner Notification: February 7th, 1975

Recall Notes:
MACK CAMPAIGN NO 55.MFG'D JAN.1, 1973 THRU AUG.14, 1974.POSSIBILITYTHAT VEHICLES EQUIPPED WITH A TRACTOR PROTECTION VALVE AN INTERFERENCE COULDOCCUR BETWEEN THE STOP LAMP SWITCH AND THE HEAD LAMP SWITCH COULD CREATE ASHORT CIRCUIT THAT WOULD INTERRUPT HEAD LAMP OPERATION.(CORRECT BY INSPECTINGAND PROVIDING ADDITIONAL CLEARANCE BETWEEN SWITCHES WHERE NECESSARY).