1975 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:
- 78V031000 on 10/11/1979
- Component:
- Suspension:multiple axle
- Manufactured:
- 02/28/1975 - 01/31/1978
- Affected:
- 33,000
- Defect:
- The tee bracket, which is mounted on the front axle of the bogie, may fail due to vibration brought on by road surface irregularities. bracket failure would leave the tee bracket unsupported and cause broken hose connector fittings. this would result in automatic application of the spring emergency brakes.
- Correction:
- The dealer will replace the defective bracket with a redesigned version.
- Notes:
- Vehicle description: trucks equipped with highway bogies.system: suspension; tee bracket.consequences of defect: automatic application of the spring emergency brakescould cause loss of vehicle control and an accident.
- 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:
- 76V004000 on 10/11/1979
- Component:
- Suspension:rear:springs:leaf spring assembly:leaf
- Affected:
- 54
- Notes:
- Mack campaign no sc071.trucks equipped with swtl-56 series rear axle.possibility that the rear suspension was assembled with an incorrect trunnionthat has a radiused spring seat, creating a line of contact between the springseat and the spring itself, subjecting these components to high stressconcentrations.if this condition exists it could ultimately lead to prematurespring failure, and permit axle assembly dislocation that could result in lossof vehicle control without warning to the driver, with possible vehicle crash.(correct by inspecting and installing specified spring trunnions thatincorporate flatspring seats).
- 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).
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