1986 Mercedes-Benz 500 — MOT failures & pass rate
The 1986 Mercedes-Benz 500 passed 81.7% of its 416 recorded MOT tests. All cars of a similar age fail 20.4% of the time, so this is 2.1pp better than the group it competes with. Failures cluster in lighting & signalling, suspension and body, structure & corrosion.
What the MOT record shows
Lighting & signalling dominates the failure mix at 10.1% of all tests — 3.9 points clear of suspension, so it is the first thing to check.
At component level the recurring items are headlamp aim, ball joint dust cover and component mounting prescribed areas — headlamp aim alone was recorded 31 times.
A 150k+ example is materially riskier than a 60-90k one: 20.0% versus 12.6%.
Advisories point at the next bill rather than this one: suspension was flagged on 18.0% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 10.1% | 42 |
| 2 | Suspension | 6.3% | 26 |
| 3 | Body, structure & corrosion | 5.3% | 22 |
| 4 | Brakes | 3.9% | 16 |
| 5 | Visibility | 3.1% | 13 |
| 6 | Emissions & environmental | 2.9% | 12 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 31 |
| 2 | Ball joint dust cover | 17 |
| 3 | Component mounting prescribed areas | 15 |
| 4 | Washers | 11 |
| 5 | Integral vehicle structure condition | 11 |
| 6 | Position lamp | 11 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 18.0% | 75 |
| 2 | Emissions & environmental | 16.6% | 69 |
| 3 | Brakes | 11.1% | 46 |
| 4 | Body, structure & corrosion | 10.6% | 44 |
| 5 | Steering | 10.3% | 43 |
| 6 | Tyres | 9.4% | 39 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 60-90k | 103 | 12.6% |
| 90-120k | 134 | 24.6% |
| 120-150k | 88 | 18.2% |
| 150k+ | 55 | 20.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 93 | 18.3% |
| 2022 | 90 | 16.7% |
| 2023 | 89 | 21.3% |
| 2024 | 69 | 15.9% |
| 2025 | 75 | 18.7% |
What to check before buying a 1986 500
On a 1986 500, lighting & signalling is what the MOT record says goes wrong most — it appeared in 10.1% of tests. Check these areas before you commit.
- Lighting & signalling (10.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (6.3% 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.
- Body, structure & corrosion (5.3% of tests): The one to take seriously on older cars — corrosion to structural areas can be costly and is an MOT failure. Typical repair: £200–£1,500+.
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 1986 Mercedes-Benz 500s pass their MOT?
81.7% of the 416 1986 Mercedes-Benz 500 MOT tests in this dataset passed — a 18.3% fail rate.
What is the most common MOT failure on a 1986 Mercedes-Benz 500?
Lighting & signalling, recorded in 10.1% of tests, followed by suspension (6.3%).
Does the 1986 500 get worse with mileage?
Its MOT fail rate rises from 12.6% in the 60-90k band to 20.0% in the 150k+ band.
Methodology & source. Based on 416 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.