- The problem
- 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 result, the anti-wheel lock warning lamp is not activated.
- The fix
- The dealer will inspect and, if necessary, replace the anti-wheel lock controller without charge to owner.
Vehicle safety record
1975 Mack HMM Problems, complaints & recalls
No owner complaints about the 1975 Mack HMM have been filed with NHTSA. It is covered by 2 recalls, the latest in April 1978 for the control unit / module.
NHTSA data checked
CAbout as many problems as a typical HMM year, for its age
- Complaints
- 0
- Recalls
- 2
- Crashes
- 0
- Fires
- 0
- Injuries
- 0
- Deaths
- 0
1975 Mack HMM recalls 2
Recall repairs are free. Your dealer fixes them whether or not you bought the car there - check your VIN at nhtsa.gov/recalls to see if yours is done. What to do
- The problem
- 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.
- The fix
- Dealer will replace the original fan with a steel fixed blade fan, free of charge.
What owners say
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No complaints about the 1975 Mack HMM yet
No owner has filed a complaint about this vehicle with NHTSA. If yours has a problem, share it here and report it to NHTSA.
Mack HMM: every year compared
All HMM years1975 Mack HMM vs rivals
| Vehicle | Complaints | Recalls | Grade | |
|---|---|---|---|---|
| 1975 Mack HMM | 0 | 2 | C | |
| 1975 Mack Mack | 1 | 1 | C | Compare |
More sales usually means more complaints, so compare similar vehicles of the same year. The grade compares each vehicle with its own model's other years.
Questions about the 1975 Mack HMM
Does the 1975 Mack HMM have any recalls?
Yes - NHTSA lists 2 recalls for the 1975 Mack HMM: control unit / module (April 1978); fan (October 1977). Recall repairs are free at any authorized dealer. Enter your VIN at nhtsa.gov/recalls to see whether yours has been fixed.
How many complaints has the 1975 Mack HMM had?
None have been filed with NHTSA so far.
Is the 1975 Mack HMM a reliable vehicle?
Its Safety Index is 50 out of 100 (grade C: about as many problems as a typical Mack HMM year, for its age). The index weighs complaints, crashes, fires, injuries, deaths and recalls against how long the vehicle has been on the road, compared with the same model's other years. It is not a measure of every repair - read the complaints and owner experiences, and have any used vehicle inspected before you buy.
What should I do if my 1975 Mack HMM has a problem?
If it is a safety problem, stop driving it if it is unsafe and contact your dealer. Report it to NHTSA at nhtsa.gov/report-a-safety-problem - enough reports start investigations and recalls - and share your experience here so other owners know what to look for.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data