1977 Mack Hmm Recalls, Complaints & Specs
4 safety recalls list the 1977 Mack Hmm. Check your own VIN below.
4 safety recalls for the 1977 Mack Hmm
Most recent first. Recall repairs are free at any authorised dealer. Click a recall for the full defect, consequence and remedy text.
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Anchorage (seat belts)
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.
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Hanger/bracket (suspension)
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…
Remedy: Dealer will reweld the insulator spring bracket at no cost to owner.
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Fan (engine and engine cooling)
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.
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Anchorage (seat belts)
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…
Remedy: Dealer will inspect and, if necessary, replace seat belt assemblies without charge to owner.
No owner complaints on file
NHTSA has no owner complaints on file for the 1977 Mack Hmm. For context, the average model year in NHTSA's database has dozens; a zero can mean a reliable vehicle, a rare one, or both.
Compare Mack Hmm model years
Recall and complaint counts for every Mack Hmm model year in NHTSA's database.
| Model year | Recalls | Complaints |
|---|---|---|
| 1972 Mack Hmm | 1 | 0 |
| 1973 Mack Hmm | 1 | 0 |
| 1974 Mack Hmm | 2 | 0 |
| 1975 Mack Hmm | 2 | 0 |
| 1976 Mack Hmm | 4 | 0 |
| 1977 Mack Hmm | 4 | 0 |
Checking a specific 1977 Mack Hmm
How do I know if my 1977 Mack Hmm has an open recall?
Enter your 17-character VIN above. The VIN is on the driver's side dashboard (visible through the windshield), the driver's door jamb sticker, and your registration or insurance card. The check runs against NHTSA's live database and tells you which campaigns list your vehicle. 4 campaigns currently list the 1977 Mack Hmm; your car may already have been repaired under some of them.
Is the recall repair free?
Yes. Under federal law, manufacturers must fix safety recalls at no charge for vehicles up to 15 years old from the date of sale to the first owner. Contact any authorised Mack dealer with your VIN and the NHTSA campaign number (for example 77V173000).
What is the difference between a recall and a complaint?
A recall is a safety campaign filed by the manufacturer or ordered by NHTSA, with a defined defect and remedy. A complaint is a report an owner sent to NHTSA; it is not verified, but patterns of complaints are what trigger NHTSA investigations and, eventually, recalls.
Other Mack models
- Mack28 complaints
- Anthem (an)12 complaints
- Granite (gr)9 complaints
- CXU6127 complaints
- Ch6 complaints
- Gu6 complaints
- CH6005 complaints
- Cxu5 complaints
Source: NHTSA recall and complaint databases and EPA fuel economy data, October 2026. Complaint counts are owner reports to NHTSA, not verified defects. Recall counts are safety campaigns that list this model year; whether a particular car was already repaired depends on its VIN. How this data is compiled.