1992 Mercedes-Benz 300 — MOT failures & pass rate
Across 2,371 MOT tests, the 1992 Mercedes-Benz 300 recorded an 82.7% pass rate. All cars of a similar age fail 23.0% of the time, so this is 5.6pp better than the group it competes with. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 11.4% of tests against 6.7% for the next-worst category.
At component level the recurring items are headlamp aim, position lamp and wipers — headlamp aim alone was recorded 122 times.
Mileage is the strongest signal on the record: 4.7% of 0-30k cars fail, rising to 19.7% once past 150k — 4.2× the risk.
The petrol cars hold up better: 15.8% fail against 21.9% for diesel, a 6.2-point gap across 2,371 tests.
Suspension is the most common advisory, noted on 28.1% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 19.6% in 2021 to 14.7% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.4% | 271 |
| 2 | Suspension | 6.7% | 158 |
| 3 | Brakes | 6.2% | 147 |
| 4 | Body, structure & corrosion | 4.4% | 104 |
| 5 | Visibility | 4.3% | 103 |
| 6 | Emissions & environmental | 3.2% | 75 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 122 |
| 2 | Position lamp | 92 |
| 3 | Wipers | 62 |
| 4 | Headlamp | 60 |
| 5 | Rigid brake pipes | 56 |
| 6 | Component mounting prescribed areas | 56 |
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 | 28.1% | 665 |
| 2 | Brakes | 26.7% | 634 |
| 3 | Emissions & environmental | 18.6% | 441 |
| 4 | Tyres | 15.0% | 355 |
| 5 | Body, structure & corrosion | 10.2% | 241 |
| 6 | Steering | 8.3% | 196 |
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 | 64 | 4.7% |
| 30-60k | 144 | 12.5% |
| 60-90k | 427 | 14.5% |
| 90-120k | 495 | 17.2% |
| 120-150k | 430 | 19.3% |
| 150k+ | 811 | 19.7% |
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 1,764 | 15.8% |
| Diesel | 607 | 21.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 576 | 19.6% |
| 2022 | 503 | 16.3% |
| 2023 | 469 | 17.9% |
| 2024 | 428 | 17.3% |
| 2025 | 395 | 14.7% |
What to check before buying a 1992 300
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 11.4% of tests. Start there.
- Lighting & signalling (11.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (6.7% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Brakes (6.2% 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 1992 Mercedes-Benz 300s pass their MOT?
82.7% of the 2,371 1992 Mercedes-Benz 300 MOT tests in this dataset passed — a 17.3% fail rate.
What is the most common MOT failure on a 1992 Mercedes-Benz 300?
Lighting & signalling, recorded in 11.4% of tests, followed by suspension (6.7%).
Does the 1992 300 get worse with mileage?
Its MOT fail rate rises from 4.7% in the 0-30k band to 19.7% in the 150k+ band.
Methodology & source. Based on 2,371 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.