Vehicle recall 79V171000 · July 12, 1979

Mack F, FM and 11 more models

The spring seat plate, located between the axle housing and the suspension springs, may deform due to spring bending.

Source: NHTSA data as of September 22, 2026. Last refreshed Sep 23, 2026, 2:43 AM UTC.

Summary: 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.
Notes: Vehicle description: trucks.system: suspension; rear axle assembly.consequences of defect: loss of vehicle control and an accident could resultdue to dislocation of axle and tire to spring interference.

Recall details

NHTSA campaign: 79V171000
Reported to NHTSA: July 12, 1979
Filed by: MACK TRUCKS, INCORPORATED
Owner notification: December 10, 1979
Vehicles potentially affected: 1,706
Initiated by: the manufacturer
Components: Suspension › Rear › Springs › Leaf spring assembly

Recall 79V171000 on nhtsa.gov, with the manufacturer’s documents

Vehicles covered

As listed by NHTSA. A recall usually covers only some vehicles of each model and year, often a production date range.

Mack F (1979): 1979
Mack FM (1979): 1979
Mack MB (1979): 1979
Mack MC (1979): 1979
Mack MR (1979): 1979
Mack R (1979): 1979
Mack RL (1979): 1979
Mack RM (1979): 1979
Mack RS (1979): 1979
Mack RWL (1979): 1979
Mack RWS (1979): 1979
Mack WL (1979): 1979
Mack WS (1979): 1979

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