2012 Mercedes-Benz C-Class — MOT failures & pass rate
Across 174,097 MOT tests, the 2012 Mercedes-Benz C-Class recorded a 78.7% pass rate. Executive cars of a similar age fail 18.4% of the time, so this is 2.9pp worse than the group it competes with. Failures cluster in suspension, brakes and tyres.
What the MOT record shows
No single area dominates — suspension (10.2%) and brakes (9.2%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are ball joint, rigid brake pipes and tread depth — ball joint alone was recorded 10,069 times.
Mileage is the strongest signal on the record: 9.9% of 0-30k cars fail, rising to 25.9% once past 150k — 2.6× the risk.
Split by fuel, diesel examples fail 4.7pp more often than petrol ones (22.5% vs 17.8%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 33.3% of tests without failing them.
The trend is worsening — 18.9% of tests failed in 2021 against 22.8% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 10.2% | 17,717 |
| 2 | Brakes | 9.2% | 15,999 |
| 3 | Tyres | 6.6% | 11,519 |
| 4 | Lighting & signalling | 5.0% | 8,759 |
| 5 | Emissions & environmental | 3.2% | 5,618 |
| 6 | Visibility | 1.5% | 2,609 |
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 | 10,069 |
| 2 | Rigid brake pipes | 9,457 |
| 3 | Tread depth | 7,014 |
| 4 | Headlamp aim | 5,645 |
| 5 | Rbt (sp) | 5,003 |
| 6 | Linkage ball joint dust cover | 4,596 |
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 | 33.3% | 58,021 |
| 2 | Tyres | 26.5% | 46,203 |
| 3 | Suspension | 20.6% | 35,791 |
| 4 | Other defects | 6.5% | 11,372 |
| 5 | Emissions & environmental | 5.1% | 8,963 |
| 6 | Visibility | 4.3% | 7,546 |
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 | 2,876 | 9.9% |
| 30-60k | 23,721 | 14.7% |
| 60-90k | 53,686 | 20.0% |
| 90-120k | 50,836 | 23.0% |
| 120-150k | 27,776 | 24.9% |
| 150k+ | 15,138 | 25.9% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 129,434 | 22.5% |
| Petrol | 44,663 | 17.8% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 36,301 | 18.9% |
| 2022 | 36,192 | 20.5% |
| 2023 | 35,311 | 21.4% |
| 2024 | 34,196 | 22.9% |
| 2025 | 32,097 | 22.8% |
What to check before buying a 2012 C-Class
On a 2012 C-Class, suspension is what the MOT record says goes wrong most — it appeared in 10.2% of tests. Check these areas before you commit.
- Suspension (10.2% 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 (9.2% 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.
- Tyres (6.6% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
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 2012 Mercedes-Benz C-Classs pass their MOT?
78.7% of the 174,097 2012 Mercedes-Benz C-Class MOT tests in this dataset passed — a 21.3% fail rate.
What is the most common MOT failure on a 2012 Mercedes-Benz C-Class?
Suspension, recorded in 10.2% of tests, followed by brakes (9.2%).
Does the 2012 C-Class get worse with mileage?
Its MOT fail rate rises from 9.9% in the 0-30k band to 25.9% in the 150k+ band.
Methodology & source. Based on 174,097 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.