2008 Mercedes-Benz S-Class — MOT failures & pass rate
Across 6,221 MOT tests, the 2008 Mercedes-Benz S-Class recorded an 81.3% pass rate. Against executive cars of a similar age (22.5% fail rate), the 2008 S-Class comes out 3.8pp better. Failures cluster in brakes, lighting & signalling and suspension.
What the MOT record shows
No single area dominates — brakes (8.3%) and lighting & signalling (6.7%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are ball joint, rbt (sp) and tread depth — ball joint alone was recorded 253 times.
Mileage is the strongest signal on the record: 8.1% of 0-30k cars fail, rising to 21.5% once past 150k — 2.7× the risk.
The petrol cars hold up better: 14.7% fail against 19.5% for diesel, a 4.8-point gap across 6,221 tests.
Brakes is the most common advisory, noted on 35.4% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Brakes | 8.3% | 513 |
| 2 | Lighting & signalling | 6.7% | 417 |
| 3 | Suspension | 6.3% | 392 |
| 4 | Emissions & environmental | 6.2% | 383 |
| 5 | Tyres | 4.8% | 296 |
| 6 | Visibility | 3.2% | 198 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 253 |
| 2 | Rbt (sp) | 237 |
| 3 | Tread depth | 223 |
| 4 | Rigid brake pipes | 193 |
| 5 | Malfunction indicator lamp | 147 |
| 6 | Position lamp | 143 |
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 | 35.4% | 2,199 |
| 2 | Tyres | 26.1% | 1,622 |
| 3 | Suspension | 22.9% | 1,424 |
| 4 | Emissions & environmental | 12.8% | 793 |
| 5 | Visibility | 4.5% | 279 |
| 6 | Other defects | 4.5% | 277 |
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 | 124 | 8.1% |
| 30-60k | 572 | 12.2% |
| 60-90k | 1,299 | 17.9% |
| 90-120k | 1,850 | 19.4% |
| 120-150k | 1,257 | 19.9% |
| 150k+ | 1,118 | 21.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 5,124 | 19.5% |
| Petrol | 1,097 | 14.7% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,450 | 18.3% |
| 2022 | 1,406 | 19.5% |
| 2023 | 1,258 | 18.2% |
| 2024 | 1,147 | 18.4% |
| 2025 | 960 | 18.9% |
What to check before buying a 2008 S-Class
The failure pattern for this year is specific enough to inspect against: brakes accounted for 8.3% of tests. Start there.
- Brakes (8.3% 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.
- Lighting & signalling (6.7% 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.
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 2008 Mercedes-Benz S-Classs pass their MOT?
81.3% of the 6,221 2008 Mercedes-Benz S-Class MOT tests in this dataset passed — a 18.7% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz S-Class?
Brakes, recorded in 8.3% of tests, followed by lighting & signalling (6.7%).
Does the 2008 S-Class get worse with mileage?
Its MOT fail rate rises from 8.1% in the 0-30k band to 21.5% in the 150k+ band.
Methodology & source. Based on 6,221 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.