2004 MG ZT — MOT failures & pass rate
5,852 MOT tests on the 2004 MG ZT are in this dataset, and 74.1% of them passed. Against large family cars of a similar age (28.0% fail rate), the 2004 ZT comes out 2.1pp better. Failures cluster in suspension, brakes and lighting & signalling.
What the MOT record shows
No single area dominates — suspension (12.4%) and brakes (11.9%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are rigid brake pipes, headlamp aim and rbt (sp) — rigid brake pipes alone was recorded 385 times.
Mileage is the strongest signal on the record: 9.4% of 0-30k cars fail, rising to 30.1% once past 150k — 3.2× the risk.
The petrol cars hold up better: 23.8% fail against 28.9% for diesel, a 5.0-point gap across 5,850 tests.
Brakes is the most common advisory, noted on 34.6% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 27.3% in 2021 to 24.1% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 12.4% | 728 |
| 2 | Brakes | 11.9% | 696 |
| 3 | Lighting & signalling | 10.8% | 630 |
| 4 | Seat belts & restraints | 5.5% | 324 |
| 5 | Body, structure & corrosion | 4.7% | 274 |
| 6 | Tyres | 4.4% | 259 |
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 | 385 |
| 2 | Headlamp aim | 353 |
| 3 | Rbt (sp) | 327 |
| 4 | SRS malfunction indicator lamp | 269 |
| 5 | Component mounting prescribed areas | 242 |
| 6 | Headlamp | 181 |
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 | 34.6% | 2,026 |
| 2 | Suspension | 30.5% | 1,783 |
| 3 | Tyres | 20.7% | 1,211 |
| 4 | Lighting & signalling | 14.1% | 828 |
| 5 | Body, structure & corrosion | 10.1% | 591 |
| 6 | Steering | 7.4% | 435 |
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 | 128 | 9.4% |
| 30-60k | 750 | 19.2% |
| 60-90k | 1,378 | 24.6% |
| 90-120k | 1,472 | 27.8% |
| 120-150k | 1,060 | 27.6% |
| 150k+ | 1,059 | 30.1% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 3,446 | 23.8% |
| Diesel | 2,404 | 28.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,538 | 27.3% |
| 2022 | 1,342 | 27.0% |
| 2023 | 1,183 | 26.6% |
| 2024 | 937 | 22.9% |
| 2025 | 852 | 24.1% |
What to check before buying a 2004 ZT
The failure pattern for this year is specific enough to inspect against: suspension accounted for 12.4% of tests. Start there.
- Suspension (12.4% 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 (11.9% 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 (10.8% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
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 MG ZTs pass their MOT?
74.1% of the 5,852 2004 MG ZT MOT tests in this dataset passed — a 25.9% fail rate.
What is the most common MOT failure on a 2004 MG ZT?
Suspension, recorded in 12.4% of tests, followed by brakes (11.9%).
Does the 2004 ZT get worse with mileage?
Its MOT fail rate rises from 9.4% in the 0-30k band to 30.1% in the 150k+ band.
Methodology & source. Based on 5,852 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.