2008 Mercedes-Benz Cl — MOT failures & pass rate
The 2008 Mercedes-Benz Cl passed 84.3% of its 573 recorded MOT tests. Coupes & convertibles of a similar age fail 21.1% of the time, so this is 5.4pp better than the group it competes with. Failures cluster in brakes, tyres and suspension.
What the MOT record shows
Brakes dominates the failure mix at 8.6% of all tests — 4.4 points clear of tyres, so it is the first thing to check.
At component level the recurring items are rbt (sp), rigid brake pipes and service brake performance — rbt (sp) alone was recorded 23 times.
A 120-150k example is materially riskier than a 30-60k one: 16.1% versus 9.6%.
Advisories point at the next bill rather than this one: brakes was flagged on 25.5% of tests without failing them.
The trend is improving — the fail rate fell from 16.7% in 2021 to 10.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Brakes | 8.6% | 49 |
| 2 | Tyres | 4.2% | 24 |
| 3 | Suspension | 3.7% | 21 |
| 4 | Lighting & signalling | 2.8% | 16 |
| 5 | Emissions & environmental | 1.2% | 7 |
| 6 | Other defects | 1.1% | 6 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rbt (sp) | 23 |
| 2 | Rigid brake pipes | 17 |
| 3 | Service brake performance | 13 |
| 4 | Registration plates | 10 |
| 5 | Ball joint | 10 |
| 6 | Parking brake performance | 8 |
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 | 25.5% | 146 |
| 2 | Suspension | 20.2% | 116 |
| 3 | Tyres | 18.1% | 104 |
| 4 | Emissions & environmental | 7.8% | 45 |
| 5 | Other defects | 4.5% | 26 |
| 6 | Road wheels | 2.6% | 15 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 30-60k | 104 | 9.6% |
| 60-90k | 232 | 16.4% |
| 90-120k | 176 | 18.8% |
| 120-150k | 31 | 16.1% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 108 | 16.7% |
| 2022 | 123 | 13.8% |
| 2023 | 134 | 18.7% |
| 2024 | 114 | 17.5% |
| 2025 | 94 | 10.6% |
What to check before buying a 2008 Cl
On a 2008 Cl, brakes is what the MOT record says goes wrong most — it appeared in 8.6% of tests. Check these areas before you commit.
- Brakes (8.6% 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 (4.2% 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.
- Suspension (3.7% 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 Cls pass their MOT?
84.3% of the 573 2008 Mercedes-Benz Cl MOT tests in this dataset passed — a 15.7% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz Cl?
Brakes, recorded in 8.6% of tests, followed by tyres (4.2%).
Does the 2008 Cl get worse with mileage?
Its MOT fail rate rises from 9.6% in the 30-60k band to 16.1% in the 120-150k band.
Methodology & source. Based on 573 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.