1980 MG B — MOT failures & pass rate
The 1980 MG B passed 81.5% of its 659 recorded MOT tests. Against all cars of a similar age (16.2% fail rate), the 1980 B comes out 2.3pp worse. Failures cluster in lighting & signalling, emissions & environmental and brakes.
What the MOT record shows
No single area dominates — lighting & signalling (9.9%) and emissions & environmental (7.6%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are non catalyst emissions, washers and service brake performance — non catalyst emissions alone was recorded 59 times.
Mileage is the strongest signal on the record: 14.5% of 0-30k cars fail, rising to 23.5% once past 90-120k.
Suspension is the most common advisory, noted on 17.2% of tests — work that passed today but is likely due soon.
The trend is worsening — 16.1% of tests failed in 2021 against 19.1% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 9.9% | 65 |
| 2 | Emissions & environmental | 7.6% | 50 |
| 3 | Brakes | 7.4% | 49 |
| 4 | Visibility | 6.7% | 44 |
| 5 | Body, structure & corrosion | 3.2% | 21 |
| 6 | Steering | 2.7% | 18 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Non catalyst emissions | 59 |
| 2 | Washers | 36 |
| 3 | Service brake performance | 24 |
| 4 | Service brake imbalance | 19 |
| 5 | Position lamp | 19 |
| 6 | Rear fog lamp | 18 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 17.2% | 113 |
| 2 | Emissions & environmental | 14.7% | 97 |
| 3 | Brakes | 7.6% | 50 |
| 4 | Body, structure & corrosion | 6.1% | 40 |
| 5 | Other defects | 5.9% | 39 |
| 6 | Tyres | 4.3% | 28 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 152 | 14.5% |
| 30-60k | 205 | 21.9% |
| 60-90k | 234 | 16.7% |
| 90-120k | 68 | 23.5% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 180 | 16.1% |
| 2022 | 134 | 17.9% |
| 2023 | 130 | 22.3% |
| 2024 | 105 | 18.1% |
| 2025 | 110 | 19.1% |
What to check before buying a 1980 B
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 9.9% of tests. Start there.
- Lighting & signalling (9.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (7.6% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Brakes (7.4% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 1980 MG Bs pass their MOT?
81.5% of the 659 1980 MG B MOT tests in this dataset passed — a 18.5% fail rate.
What is the most common MOT failure on a 1980 MG B?
Lighting & signalling, recorded in 9.9% of tests, followed by emissions & environmental (7.6%).
Does the 1980 B get worse with mileage?
Its MOT fail rate rises from 14.5% in the 0-30k band to 23.5% in the 90-120k band.
Methodology & source. Based on 659 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.