1974 MACK U Recalls (6)
- Campaign:
- 78V068000 on 10/11/1979
- Component:
- Service brakes, air:antilock:control unit/module
- Manufactured:
- 09/30/1974 - 02/29/1976
- Affected:
- 9,700
- Defect:
- 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.
- Correction:
- The dealer will inspect and, if necessary, replace the anti-wheel lock controller without charge to owner.
- 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.
- Campaign:
- 78V171000 on 10/11/1979
- Component:
- Steering:linkages:knuckle:spindle:arm
- Affected:
- 2,100
- Defect:
- Deficiencies, in the form of forging laps, cracks and excessive decarburization during heat treatment, exist in the steering knuckles. stresses imposed with integral hydraulic power steering may lead to a failure in the area of the steering arm attaching boss. this type of failure would cause loss of steering control.
- Correction:
- Dealer will inspect and, if necessary, replace the left steering knuckle with an improved type of knuckle.
- Notes:
- Vehicle description: truck tractors.system: steering; steering knuckle.consequences of defect: loss of steering control could cause a vehicleaccident.
- Campaign:
- 77V173000 on 10/11/1979
- Component:
- Engine and engine cooling:cooling system:fan
- Affected:
- 48,000
- Defect:
- 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.
- Correction:
- Dealer will replace the original fan with a steel fixed blade fan, free of charge.
- 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.
- Campaign:
- 75V190000 on 10/11/1979
- Component:
- Service brakes, air:antilock:interconnecting assembly(wiring)
- Affected:
- 3,400
- 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).
- Campaign:
- 75V192000 on 10/11/1979
- Component:
- Service brakes, air:supply:hoses, lines/piping, and fittings
- Affected:
- 1,200
- 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).
- Campaign:
- 74V227000 on 10/11/1979
- Component:
- Exterior lighting:headlights:switch
- Affected:
- 1,023
- 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).
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