1990 Mercedes-Benz 300 — MOT failures & pass rate
The 1990 Mercedes-Benz 300 passed 81.7% of its 1,859 recorded MOT tests. That is 3.5 percentage points better than all cars of a similar age, which fail at 21.8%. Failures cluster in lighting & signalling, brakes and suspension.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 11.7% of tests against 8.2% for the next-worst category.
At component level the recurring items are service brake performance, headlamp aim and position lamp — service brake performance alone was recorded 66 times.
A 150k+ example is materially riskier than a 0-30k one: 22.9% versus 18.4%.
Suspension is the most common advisory, noted on 26.3% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 20.1% in 2021 to 18.5% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.7% | 217 |
| 2 | Brakes | 8.2% | 152 |
| 3 | Suspension | 6.5% | 120 |
| 4 | Body, structure & corrosion | 6.0% | 111 |
| 5 | Visibility | 4.7% | 88 |
| 6 | Emissions & environmental | 3.5% | 65 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Service brake performance | 66 |
| 2 | Headlamp aim | 65 |
| 3 | Position lamp | 64 |
| 4 | Rigid brake pipes | 51 |
| 5 | Washers | 48 |
| 6 | Component mounting prescribed areas | 48 |
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 | 26.3% | 488 |
| 2 | Brakes | 23.8% | 443 |
| 3 | Emissions & environmental | 20.2% | 375 |
| 4 | Tyres | 14.0% | 260 |
| 5 | Body, structure & corrosion | 11.2% | 209 |
| 6 | Steering | 7.6% | 142 |
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 | 87 | 18.4% |
| 30-60k | 185 | 13.5% |
| 60-90k | 258 | 16.3% |
| 90-120k | 352 | 13.9% |
| 120-150k | 339 | 18.0% |
| 150k+ | 634 | 22.9% |
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 1,527 | 17.9% |
| Diesel | 332 | 19.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 468 | 20.1% |
| 2022 | 380 | 18.4% |
| 2023 | 341 | 16.7% |
| 2024 | 346 | 17.1% |
| 2025 | 324 | 18.5% |
What to check before buying a 1990 300
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 11.7% of tests. Start there.
- Lighting & signalling (11.7% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.2% 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.
- Suspension (6.5% 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.
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 1990 Mercedes-Benz 300s pass their MOT?
81.7% of the 1,859 1990 Mercedes-Benz 300 MOT tests in this dataset passed — a 18.3% fail rate.
What is the most common MOT failure on a 1990 Mercedes-Benz 300?
Lighting & signalling, recorded in 11.7% of tests, followed by brakes (8.2%).
Does the 1990 300 get worse with mileage?
Its MOT fail rate rises from 18.4% in the 0-30k band to 22.9% in the 150k+ band.
Methodology & source. Based on 1,859 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.