1977 Mack HMM: complaints, problems and recalls
Explore the records behind recurring owner reports.
Key facts
0 owner complaints analyzed
4 distinct recall campaigns
Not available median reported failure mileage
Scope: 1977 model year. Data snapshot: . 0 complaints include usable failure mileage.
Most common problems
No owner complaints are recorded for this selection. A complaint can name multiple components.
Component breakdown
Number of unique complaints naming each component. Top eight shown.
No usable records for this chart.
| Category | Count |
|---|
No records.
Reported problems by failure mileage
Complaint counts in mileage bands. These are not failure rates per vehicle or mile.
| Category | Count |
|---|---|
| Under 25,000 | 0 |
| 25,000 to 49,999 | 0 |
| 50,000 to 74,999 | 0 |
| 75,000 to 99,999 | 0 |
| 100,000 to 149,999 | 0 |
| 150,000 and above | 0 |
Under 25,000: 0; 25,000 to 49,999: 0; 50,000 to 74,999: 0; 75,000 to 99,999: 0; 100,000 to 149,999: 0; 150,000 and above: 0
No usable failure mileage is recorded. 0 complaints have missing, zero or invalid mileage.
Complaints over time
Year the complaint was filed, not the vehicle model year or incident year. The snapshot year is partial.
No usable records for this chart.
| Category | Count |
|---|
No records.
Pattern summary
There is not enough complaint evidence to summarize patterns.
Calculated from recorded counts. An AI narrative has not been published for this selection.
Examples from the source records
Examples provide context, not a representative sample or a verified diagnosis.
Recall history
4 distinct campaigns affect this selection. Announcement dates below are different from vehicle model years. A campaign may cover multiple years.
77V173000 · Engine And Engine Cooling:Cooling System:Fan
Reported: 1977-10-12 (October 12, 1977)
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.
NHTSA campaign record ↗77V174000 · Seat Belts:Front:Anchorage
Reported: 1977-10-12 (October 12, 1977)
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.
NHTSA campaign record ↗77V204000 · Seat Belts:Front:Anchorage
Reported: 1977-11-21 (November 21, 1977)
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.
NHTSA campaign record ↗77V205000 · Suspension:Rear:Springs:Leaf Spring Assembly:Hanger/Bracket
Reported: 1977-11-21 (November 21, 1977)
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.
NHTSA campaign record ↗