Vehicle recall 78V171000 · August 8, 1978

Mack F, MB and 2 more models

Deficiencies, in the form of forging laps, cracks and excessive decarburization during heat treatment, exist in the steering knuckles.

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

Summary: 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.
Remedy: 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.

Recall details

NHTSA campaign: 78V171000
Reported to NHTSA: August 8, 1978
Filed by: MACK TRUCKS, INCORPORATED
Owner notification: August 10, 1979
Vehicles potentially affected: 2,100
Initiated by: the manufacturer
Components: Steering › Linkages › Knuckle › Spindle › Arm

Recall 78V171000 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 (1971-1974): 1974, 1973, 1972, 1971
Mack MB (1971-1974): 1974, 1973, 1972, 1971
Mack R (1971-1974): 1974, 1973, 1972, 1971
Mack U (1971-1974): 1974, 1973, 1972, 1971

Has your Mack been repaired?

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