Model year record

1977 MACK HMM

4 recall campaigns on file for this model year. No owner complaints on file.

Recalls

Recall campaignNHTSA 77V204000

Seat belts: front: anchorage

Component
Seat belts: front: anchorage
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
11
Reported to NHTSA
1977-11-21
Owners notified
1978-04-14

Defect description

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.

Manufacturer remedy

DEALER WILL RELOCATE THE TETHER BELT FLOOR ANCHORAGE TO CORRECT THE PROBLEM, WITHOUT CHARGE TO OWNER.

Recall campaignNHTSA 77V205000

Suspension: rear: springs: leaf spring assembly: hanger/bracket

Component
Suspension: rear: springs: leaf spring assembly: hanger/bracket
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
7,400
Reported to NHTSA
1977-11-21
Owners notified
1978-03-14

Defect description

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.

Manufacturer remedy

DEALER WILL REWELD THE INSULATOR SPRING BRACKET AT NO COST TO OWNER.

Recall campaignNHTSA 77V174000

Seat belts: front: anchorage

Component
Seat belts: front: anchorage
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
6,591
Reported to NHTSA
1977-10-12
Owners notified
1978-08-23

Defect description

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.

Manufacturer remedy

DEALER WILL INSPECT AND, IF NECESSARY, REPLACE SEAT BELT ASSEMBLIES WITHOUT CHARGE TO OWNER.

Recall campaignNHTSA 77V173000

Engine and engine cooling: cooling system: fan

Component
Engine and engine cooling: cooling system: fan
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
48,000
Reported to NHTSA
1977-10-12
Owners notified
1978-03-23

Defect description

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.

Manufacturer remedy

DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.

Owner complaints

A complaint is one person's report to a federal agency. It is not a finding.

No complaints recorded for this model year.

Safety recall repairs are provided free of charge by franchised dealers, regardless of vehicle age or mileage. This page displays aggregated data for the model year. To check recall status for a specific vehicle, search its VIN at nhtsa.gov.