1986 Mercedes 508d MOT Pass Rate
Pass rate for 508d models manufactured in 1986, based on 40 real MOT test results.
Data from official DVSA MOT testing records
1986 Mercedes 508d MOT Analysis
The 1986 Mercedes 508d has an MOT pass rate of 37.5% based on 40 tests — significantly below the UK average for UK vehicles. Cars of this vintage present for MOT with an average of 216,597 miles on the odometer. With a 62.5% failure rate, the 1986 508d is rated as "Very Poor" for MOT reliability.
The leading cause of MOT failure for the 1986 Mercedes 508d is Lamps, reflectors and electrical equipment, responsible for 20.0% of failures. Lighting failures cover all external lights: headlights, tail lights, brake lights, indicators, fog lights, and reflectors. A single blown bulb will cause an MOT fail. This is one of the most preventable failure categories. Typical repair costs range from £5–50. Tyres is the second most common issue at 17.5%. Brakes follows at 17.5%.
Top failures specific to 1986 models only. The overall 508d page may show different rankings.
What Fails Most
What Fails on This Car?
Click a category to see specific failure items.
View as table
| Rank | Failure Category | Rate (%) | Count |
|---|---|---|---|
| 1 | Lamps, Reflectors And Electrical Equipment | 20.0% | 8 |
| 2 | Tyres | 17.5% | 7 |
| 3 | Brakes | 17.5% | 7 |
| 4 | Steering | 7.5% | 3 |
| 5 | Visibility | 5.0% | 2 |
| 6 | Body, Chassis, Structure | 5.0% | 2 |
| 7 | Suspension | 2.5% | 1 |
| 8 | Noise, Emissions And Leaks | 2.5% | 1 |
Failures per 10,000 Miles
avg. 216,597 miFor every 10,000 miles driven, this shows what percentage of MOT tests fail for each category. This accounts for how far cars are actually driven, not just raw pass/fail counts.
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| Category | Rate / 10K mi | Raw % | Count |
|---|---|---|---|
| Lamps & Electrical | 0.92 | 20.0% | 8 |
| Tyres | 0.81 | 17.5% | 7 |
| Brakes | 0.81 | 17.5% | 7 |
| Steering | 0.35 | 7.5% | 3 |
| Visibility | 0.23 | 5.0% | 2 |
| Body & Structure | 0.23 | 5.0% | 2 |
| Suspension | 0.12 | 2.5% | 1 |
| Noise, emissions and leaks | 0.12 | 2.5% | 1 |
Mileage Statistics
Mileage-adjusted failure rate — accounts for how much this model year is typically driven.
About This Data
The 1986 Mercedes 508d has an MOT pass rate of 37.5% based on 40 tests — significantly below the UK average for UK vehicles. Cars of this vintage present for MOT with an average of 216,597 miles on the odometer. With a 62.5% failure rate, the 1986 508d is rated as "Very Poor" for MOT reliability.
If you own or are considering buying a 1986 Mercedes 508d, be prepared for above-average maintenance costs. Before your MOT, pay particular attention to lamps, reflectors and electrical equipment: Walk around the car and check every light — headlights (dipped and main beam), side lights, tail lights, brake lights, indicators, hazard lights, reverse light, rear fog light, and number plate lights. Replace any blown bulbs before the test. With an average mileage of 216,597 miles, these vehicles are in the higher-mileage bracket where wear-related failures become more common.
Lamps, reflectors and electrical equipment — 20.0% of failures
Lamps, reflectors and electrical equipment issues account for 20.0% of MOT failures on 1986 Mercedes 508d models. Lighting failures cover all external lights: headlights, tail lights, brake lights, indicators, fog lights, and reflectors. A single blown bulb will cause an MOT fail. This is one of the most preventable failure categories. Typical repair costs: £5–50. Pre-MOT check: Walk around the car and check every light — headlights (dipped and main beam), side lights, tail lights, brake lights, indicators, hazard lights, reverse light, rear fog light, and number plate lights. Replace any blown bulbs before the test.
Tyres — 17.5% of failures
Tyres issues account for 17.5% of MOT failures on 1986 Mercedes 508d models. Tyre failures include tread depth below the legal minimum of 1.6mm, cuts, bulges, exposed cords, and incorrect tyre pressure. Tyres are one of the most common and easiest-to-prevent MOT failures. Typical repair costs: £50–200 per tyre. Pre-MOT check: Check tread depth with a 20p coin — if the outer band is visible, the tyre is too worn. Look for bulges, cuts, or embedded objects. Ensure all tyres match the recommended size and load rating.
Brakes — 17.5% of failures
Brakes issues account for 17.5% of MOT failures on 1986 Mercedes 508d models. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. Typical repair costs: £150–400. Pre-MOT check: Listen for squealing or grinding noises. Check brake pedal feel — if it feels spongy or goes to the floor, have the system inspected immediately. Look at brake pad thickness through the wheel spokes (minimum 3mm).
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.