Mercedes-Benz 308 D MOT pass rate & common failures
The Mercedes-Benz 308 D appears in 1,146 MOT tests spanning model years 1981–2019, and 68.1% of them passed. That is 8.0 percentage points worse than all cars of a similar age, which fail at 24.0%. Its most common failure areas are lighting & signalling, brakes and suspension.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 22.9% of tests against 19.2% for the next-worst category.
At component level the recurring items are component mounting prescribed areas, service brake performance and headlamp aim — component mounting prescribed areas alone was recorded 152 times.
A 150k+ example is materially riskier than a 0-30k one: 34.1% versus 21.9%.
Brakes is the most common advisory, noted on 40.1% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 33.0% in 2021 to 30.7% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every 308 D model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 1989 | 116 | 73.3% | 26.7% | Brakes |
| 1990 | 88 | 64.8% | 35.2% | Brakes |
| 1991 | 37 | 62.2% | 37.8% | Lighting & signalling |
| 1992 | 54 | 66.7% | 33.3% | Brakes |
| 1993 | 69 | 69.6% | 30.4% | Lighting & signalling |
| 1994 | 40 | 65.0% | 35.0% | Lighting & signalling |
| 1995 | 94 | 63.8% | 36.2% | Brakes |
| 1996 | 91 | 79.1% | 20.9% | Lighting & signalling |
| 1997 | 170 | 70.6% | 29.4% | Brakes |
| 1998 | 174 | 65.5% | 34.5% | Lighting & signalling |
| 1999 | 78 | 61.5% | 38.5% | Lighting & signalling |
| 2000 | 34 | 73.5% | 26.5% | Lighting & signalling |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 22.9% | 262 |
| 2 | Brakes | 19.2% | 220 |
| 3 | Suspension | 12.4% | 142 |
| 4 | Body, structure & corrosion | 12.2% | 140 |
| 5 | Steering | 6.9% | 79 |
| 6 | Visibility | 6.7% | 77 |
| 7 | Tyres | 2.8% | 32 |
| 8 | Emissions & environmental | 2.5% | 29 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Component mounting prescribed areas | 152 |
| 2 | Service brake performance | 121 |
| 3 | Headlamp aim | 97 |
| 4 | Headlamp | 86 |
| 5 | Rear fog lamp | 77 |
| 6 | Service brake imbalance | 77 |
| 7 | Position lamp | 75 |
| 8 | Exhaust system | 67 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 40.1% | 459 |
| 2 | Suspension | 32.0% | 367 |
| 3 | Body, structure & corrosion | 25.7% | 294 |
| 4 | Lighting & signalling | 20.2% | 232 |
| 5 | Emissions & environmental | 20.2% | 232 |
| 6 | Steering | 13.8% | 158 |
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 | 32 | 21.9% |
| 30-60k | 92 | 28.3% |
| 60-90k | 204 | 24.0% |
| 90-120k | 182 | 35.2% |
| 120-150k | 138 | 36.2% |
| 150k+ | 490 | 34.1% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 267 | 33.0% |
| 2022 | 267 | 33.7% |
| 2023 | 222 | 31.5% |
| 2024 | 198 | 29.8% |
| 2025 | 192 | 30.7% |
What to check before buying a Mercedes-Benz 308 D
- Lighting & signalling (22.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (19.2% 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 (12.4% 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
What is the MOT pass rate for the Mercedes-Benz 308 D?
68.1% of the 1,146 Mercedes-Benz 308 D MOT tests in this dataset passed, a 31.9% fail rate, across model years 1981–2019.
What does the Mercedes-Benz 308 D most often fail its MOT on?
Lighting & signalling, recorded in 22.9% of tests, then brakes (19.2%).
How much does mileage affect 308 D MOT results?
Fail rates run at 21.9% for cars in the 0-30k band and 34.1% for 150k+, a 12.2-point difference.
Methodology & source. Based on 1,146 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.