1972-1977 · 6 model years

Mack HMM Problems by year

Owners have filed 0 complaints about the Mack HMM across 6 model years, and it has 6 recalls.

Share your HMM experience Compare years 6 recalls

Complaints: 0
Recalls: 6
Crashes: 0
Fires: 0
Injuries: 0
Deaths: 0

HMM complaints by model year

01972 1973 1974 1975 1976 1977

Highlighted: the year with the most complaints for its age. Older vehicles have had more time to collect complaints - the Safety Index grade allows for that.

Year	Recalls	Top problem	Grade
1977	4	-	D
1976	4	-	D
1975	2	-	C
1974	2	-	C
1973	1	-	B
1972	1	-	B

Mack HMM recalls 6

Service brakes: control unit / module

78V068000Apr 4, 19789,700 vehicles affected

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...

Covers1974 Mack HMM 1975 Mack HMM 1976 Mack HMM +36 more

Suspension: hanger / bracket

77V205000Nov 21, 19777,400 vehicles affected

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...

Covers1977 Mack HMM +11 more

Seat belts: anchorage

77V204000Nov 21, 197711 vehicles affected

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...

Covers1976 Mack HMM 1977 Mack HMM

Seat belts: anchorage

77V174000Oct 12, 19776,591 vehicles affected

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...

Covers1977 Mack HMM +8 more

Engine and engine cooling: fan

77V173000Oct 12, 197748,000 vehicles affected

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.

Covers1972 Mack HMM 1973 Mack HMM 1974 Mack HMM 1975 Mack HMM 1976 Mack HMM 1977 Mack HMM +78 more

Power train: universal joint

76V118000Jul 28, 1976105 vehicles affected

Covers1976 Mack HMM +2 more

Questions about the Mack HMM

Which Mack HMM years have the fewest complaints?

Among model years that have been on the road for at least three years, 1972, 1973 have the best Safety Index - the fewest complaints, crashes and recalls for their age compared with other HMM years. Always check the exact vehicle's recalls by VIN before you buy.

How many recalls does the Mack HMM have?

NHTSA lists 6 recalls across all Mack HMM model years. Each year's page lists the recalls for that year; check your own vehicle by VIN at nhtsa.gov/recalls to see whether the repair has been done.

Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked daily. Complaints are owners' own reports and are not verified. How we use the data