1987 Mercedes-Benz 300 — MOT failures & pass rate
The 1987 Mercedes-Benz 300 passed 84.6% of its 1,606 recorded MOT tests. Against all cars of a similar age (20.6% fail rate), the 1987 300 comes out 5.1pp better. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
No single area dominates — lighting & signalling (9.2%) and suspension (6.3%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, component mounting prescribed areas and ball joint dust cover — headlamp aim alone was recorded 77 times.
Mileage matters less than usual here: the 1987 300 fails 19.1% of the time in the 0-30k band and 22.6% at 150k+, a spread of only 3.5 points.
Suspension is the most common advisory, noted on 20.1% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 17.4% in 2021 to 13.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 9.2% | 148 |
| 2 | Suspension | 6.3% | 101 |
| 3 | Brakes | 5.7% | 91 |
| 4 | Body, structure & corrosion | 4.0% | 64 |
| 5 | Visibility | 4.0% | 64 |
| 6 | Emissions & environmental | 3.1% | 50 |
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 | 77 |
| 2 | Component mounting prescribed areas | 67 |
| 3 | Ball joint dust cover | 51 |
| 4 | Service brake performance | 49 |
| 5 | Washers | 42 |
| 6 | Wipers | 38 |
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 | 20.1% | 322 |
| 2 | Brakes | 15.1% | 243 |
| 3 | Emissions & environmental | 13.3% | 214 |
| 4 | Body, structure & corrosion | 11.1% | 178 |
| 5 | Tyres | 8.5% | 137 |
| 6 | Steering | 8.3% | 133 |
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 | 89 | 19.1% |
| 30-60k | 203 | 6.4% |
| 60-90k | 438 | 12.8% |
| 90-120k | 392 | 16.3% |
| 120-150k | 276 | 18.5% |
| 150k+ | 208 | 22.6% |
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 1,466 | 14.6% |
| Diesel | 140 | 24.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 351 | 17.4% |
| 2022 | 337 | 14.2% |
| 2023 | 316 | 16.1% |
| 2024 | 300 | 15.7% |
| 2025 | 302 | 13.6% |
What to check before buying a 1987 300
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 9.2% of tests. Start there.
- Lighting & signalling (9.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (6.3% 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 (5.7% 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 1987 Mercedes-Benz 300s pass their MOT?
84.6% of the 1,606 1987 Mercedes-Benz 300 MOT tests in this dataset passed — a 15.4% fail rate.
What is the most common MOT failure on a 1987 Mercedes-Benz 300?
Lighting & signalling, recorded in 9.2% of tests, followed by suspension (6.3%).
Does the 1987 300 get worse with mileage?
Its MOT fail rate rises from 19.1% in the 0-30k band to 22.6% in the 150k+ band.
Methodology & source. Based on 1,606 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.