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AnyRecalls

1977 Mack HMM recalls

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

4 recalls found in NHTSA data as of September 22, 2026

For the 1977 Mack HMM. These apply to the model and year, not to one particular vehicle: check your VIN to see whether yours is included and whether it has been repaired.

Has your Mack been repaired?

Recalls here come from NHTSA’s records for the model and year. Not every vehicle of a model is included in every recall, and this site can’t see whether a repair has been done. Only a VIN lookup can tell you that.

NHTSA’s VIN search doesn’t show recalls that were already repaired, recalls more than 15 years old, or some small manufacturers’ recalls. A Mack dealer can also check your VIN. Recall repairs are free.

1977 Mack HMM recalls, newest first

November 21, 1977NHTSA 77V2050007,400 vehicles potentially affected

Suspension › Rear › Springs › Leaf spring assembly › Hanger/bracket

Summary
A deficiency exists in the welds securing the rear spring insulator bracket to the axle housing. This is due to improper positioning of the weld, in relationship to the bracket and axle housing. Failure of the welds would cause separation of the spring insulator bracket and the axle housing, resulting in improper alignment of the affected axle.
Remedy
Dealer will reweld the insulator spring bracket at no cost to owner.

This recall on nhtsa.gov

November 21, 1977NHTSA 77V20400011 vehicles potentially affected

Seat belts › Front › Anchorage

Summary
The involved vehicles do not conform to federal motor vehicle safety standard nos. 207, "seating systems", and 210, "seat belt assembly anchorages". Vehicles equipped with viking t-bar seats have the seat belt anchorage located under the seat. The tether belt ruptured when subjected to the forces required in the safety test.
Remedy
Dealer will relocate the tether belt floor anchorage to correct the problem, without charge to owner.

This recall on nhtsa.gov

October 12, 1977NHTSA 77V1740006,591 vehicles potentially affected

Seat belts › Front › Anchorage

Summary
The involved vehicles do not conform to federal motor vehicle safety standard no. 209, "seatbelt assemblies". Although the seatbelts in question performed marginally with respect to the 5000 lb. Load requirement, additional testing confirmed that the anchor could fail, allowing either the anchor to slip over the hold-down nut or the anchor to separate into two pieces.
Remedy
Dealer will inspect and, if necessary, replace seat belt assemblies without charge to owner.

This recall on nhtsa.gov

October 12, 1977NHTSA 77V17300048,000 vehicles potentially affected

Engine and engine cooling › Cooling system › Fan

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.
Remedy
Dealer will replace the original fan with a steel fixed blade fan, free of charge.

This recall on nhtsa.gov

Owner complaints

No owner complaints about the 1977 Mack HMM were found in NHTSA’s complaint data.

Other Mack HMM years

Other 1977 Mack models

Questions

Does the 1977 Mack HMM have any recalls?
4 recalls found in NHTSA data as of September 22, 2026, covering: suspension, seat belts, engine and engine cooling. Recalls apply to the model and year; whether a particular vehicle is included, and whether it has been repaired, depends on its VIN.
How do I check if my 1977 Mack HMM recall has been fixed?
Enter your 17-character VIN at nhtsa.gov/recalls, or ask a Mack dealer. Recall repairs are free. NHTSA's VIN search doesn't list recalls that were already repaired.
How many complaints have owners filed about the 1977 Mack HMM?
0 complaints filed with NHTSA. Complaints are unverified reports from the public that NHTSA uses to decide what to investigate.