2004 Mercedes-Benz Cl 500 — MOT failures & pass rate
885 MOT tests on the 2004 Mercedes-Benz Cl 500 are in this dataset, and 84.2% of them passed. Against all cars of a similar age (27.7% fail rate), the 2004 Cl 500 comes out 11.9pp better. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (7.0%) and lighting & signalling (6.9%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are rigid brake pipes, ball joint and shock absorbers — rigid brake pipes alone was recorded 29 times.
A 150k+ example is materially riskier than a 30-60k one: 19.7% versus 10.8%.
Advisories point at the next bill rather than this one: brakes was flagged on 31.1% of tests without failing them.
The trend is improving — the fail rate fell from 16.8% in 2021 to 15.2% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 7.0% | 62 |
| 2 | Lighting & signalling | 6.9% | 61 |
| 3 | Brakes | 4.4% | 39 |
| 4 | Tyres | 3.6% | 32 |
| 5 | Visibility | 3.3% | 29 |
| 6 | Steering | 1.6% | 14 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rigid brake pipes | 29 |
| 2 | Ball joint | 28 |
| 3 | Shock absorbers | 25 |
| 4 | Pins and bushes | 22 |
| 5 | Headlamp aim | 22 |
| 6 | Service brake performance | 22 |
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 | 31.1% | 275 |
| 2 | Suspension | 26.9% | 238 |
| 3 | Tyres | 17.0% | 150 |
| 4 | Lighting & signalling | 11.1% | 98 |
| 5 | Other defects | 9.0% | 80 |
| 6 | Body, structure & corrosion | 8.7% | 77 |
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 | 93 | 10.8% |
| 60-90k | 241 | 17.8% |
| 90-120k | 273 | 15.8% |
| 120-150k | 181 | 14.9% |
| 150k+ | 71 | 19.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 208 | 16.8% |
| 2022 | 184 | 14.1% |
| 2023 | 188 | 16.5% |
| 2024 | 160 | 16.3% |
| 2025 | 145 | 15.2% |
What to check before buying a 2004 Cl 500
On a 2004 Cl 500, suspension is what the MOT record says goes wrong most — it appeared in 7.0% of tests. Check these areas before you commit.
- Suspension (7.0% 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 (6.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (4.4% 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 2004 Mercedes-Benz Cl 500s pass their MOT?
84.2% of the 885 2004 Mercedes-Benz Cl 500 MOT tests in this dataset passed — a 15.8% fail rate.
What is the most common MOT failure on a 2004 Mercedes-Benz Cl 500?
Suspension, recorded in 7.0% of tests, followed by lighting & signalling (6.9%).
Does the 2004 Cl 500 get worse with mileage?
Its MOT fail rate rises from 10.8% in the 30-60k band to 19.7% in the 150k+ band.
Methodology & source. Based on 885 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.