2008 Mercedes-Benz B-Class — MOT failures & pass rate
The 2008 Mercedes-Benz B-Class passed 72.7% of its 25,457 recorded MOT tests. MPVs of a similar age fail 28.3% of the time, so this is 1.1pp better than the group it competes with. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (13.5%) and lighting & signalling (13.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are joints, coil spring and ball joint — joints alone was recorded 1,984 times.
Condition tracks the odometer closely. Failures run at 16.2% in the 0-30k band and 30.6% in the 150k+ band, a 14.4-point spread.
Split by fuel, diesel examples fail 2.1pp more often than petrol ones (28.3% vs 26.1%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 41.3% of tests without failing them.
The trend is worsening — 25.4% of tests failed in 2021 against 28.4% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 13.5% | 3,441 |
| 2 | Lighting & signalling | 13.0% | 3,302 |
| 3 | Brakes | 11.3% | 2,882 |
| 4 | Body, structure & corrosion | 8.0% | 2,048 |
| 5 | Visibility | 6.6% | 1,688 |
| 6 | Tyres | 5.0% | 1,276 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Joints | 1,984 |
| 2 | Coil spring | 1,731 |
| 3 | Ball joint | 1,409 |
| 4 | Rigid brake pipes | 1,383 |
| 5 | Washers | 1,347 |
| 6 | Headlamp aim | 1,137 |
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 | 41.3% | 10,519 |
| 2 | Tyres | 28.1% | 7,162 |
| 3 | Suspension | 22.6% | 5,760 |
| 4 | Other defects | 17.0% | 4,326 |
| 5 | Body, structure & corrosion | 13.5% | 3,432 |
| 6 | Lighting & signalling | 9.0% | 2,292 |
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 | 322 | 16.2% |
| 30-60k | 2,742 | 19.0% |
| 60-90k | 8,148 | 26.0% |
| 90-120k | 8,597 | 28.9% |
| 120-150k | 4,208 | 31.2% |
| 150k+ | 1,411 | 30.6% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 13,573 | 28.3% |
| Petrol | 11,884 | 26.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 5,770 | 25.4% |
| 2022 | 5,664 | 26.9% |
| 2023 | 5,212 | 27.6% |
| 2024 | 4,710 | 28.7% |
| 2025 | 4,101 | 28.4% |
What to check before buying a 2008 B-Class
On a 2008 B-Class, suspension is what the MOT record says goes wrong most — it appeared in 13.5% of tests. Check these areas before you commit.
- Suspension (13.5% 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.
- Lighting & signalling (13.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (11.3% 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.
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 B-Classs pass their MOT?
72.7% of the 25,457 2008 Mercedes-Benz B-Class MOT tests in this dataset passed — a 27.3% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz B-Class?
Suspension, recorded in 13.5% of tests, followed by lighting & signalling (13.0%).
Does the 2008 B-Class get worse with mileage?
Its MOT fail rate rises from 16.2% in the 0-30k band to 30.6% in the 150k+ band.
Methodology & source. Based on 25,457 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.