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#BS-1977-MACHMM-74CA

1977 Mack Hmm

Based on reports from 0 owners and 4 recalls for this exact model.

Complaints

Crashes

Fires

Recalls

TSBs

✅

Preliminary Verdict

Green Light

Based on 0 complaints, 0 crashes, 0 fires, and 4 recalls.

See full verdict with buy/skip conditions

Preview: What's in your full report

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30,000-Mile Cost Projection

Best Case

$X,XXX

Most Likely

$X,XXX

Worst Case

$X,XXX

Includes fuel costs, common repairs, and recall riskUnlock

Also in your report

Owner Intelligence

AI-synthesized themes from real complaints

Buyer Lot Checklist

Questions, test drive checks, walk-away triggers

Negotiation Talking Points

Data-backed dollar deductions

Buy / Skip Verdict

Final recommendation with conditions

10 sections total in the full reportUnlock all

Don't negotiate blind — know what this car costs to own

Repair costs • Negotiation scripts • Mechanic checklist • Buy/skip verdict

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Recall History (4 recalls)

77V173000Mar 1978

ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN

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.

77V174000Aug 1978

SEAT BELTS:FRONT:ANCHORAGE

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.

77V204000Apr 1978

SEAT BELTS:FRONT:ANCHORAGE

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.

77V205000Mar 1978

SUSPENSION:REAR:SPRINGS:LEAF SPRING ASSEMBLY:HANGER/BRACKET

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.

Recall severity analysis & seller scripts

The full report rates each recall's severity and gives you scripts for asking the seller about recall completion.

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About this data

NHTSA Complaints

Federal database of owner-filed safety complaints. 0 records for this vehicle.

NHTSA Recalls

Manufacturer-issued safety recalls. 4 recalls found for this vehicle.

Repair Cost Data

Real-world repair costs from owner reports and independent databases.

Other Mack Hmm Model Years

1977 1976 1975 1974 1973 1972

View all Mack Hmm years →

1977 Mack Hmm: Frequently Asked Questions

What is the most common problem with the 1977 Mack Hmm?

Based on NHTSA data, the 1977 Mack Hmm has 0 total complaints on file.

Is the 1977 Mack Hmm reliable?

The 1977 Mack Hmm has 0 complaints, 0 crash reports, and 0 fire reports filed with NHTSA. The full report analyzes whether these numbers indicate real risk or are proportional to the vehicle’s popularity.

How much does it cost to fix 1977 Mack Hmm problems?

Repair costs vary by issue. The full BumperScan report includes detailed repair cost estimates (low/median/high) for every major issue, plus a 30,000-mile total cost of ownership projection.

Does the 1977 Mack Hmm have any recalls?

Yes, the 1977 Mack Hmm has 4 recalls on record. The full report includes recall severity analysis and scripts for asking the seller about recall completion.

What mileage do Mack Hmm problems start?

Mileage data is limited for this vehicle. The full report analyzes available data to identify failure patterns by mileage range.

What’s in the full report?

10 sections of AI analysis: severity-ranked issues, component scores (0-100), 30K-mile cost projection, failure timeline by mileage, recall details with seller scripts, owner sentiment analysis, mechanic checklist, buyer lot checklist, negotiation ammo with dollar figures, and a buy/skip verdict.

How is this different from free NHTSA data?

NHTSA gives you raw complaint text. BumperScan cross-references 2.1M+ complaints with community repair cost data, EPA fuel data, and recall records — then uses AI to synthesize it into actionable advice with dollar figures.

How is this different from Carfax?

Carfax is VIN-specific history ($45/report). BumperScan is model-level reliability intelligence — what problems this car is known for, what they cost, and whether you should buy it. Complementary, not competing.

What if the report isn’t useful?

100% money-back guarantee. If the report doesn’t help you make a more informed decision, we’ll refund you — no questions asked.

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10 sections of AI analysis based on 0 owner reports. Know before you buy.

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