Riley Merlin common MOT failures and failure rate
What a Riley Merlin fails its MOT on, from real DVSA test data, and the part that resolves each item.
Based on 81 MOT tests in DVSA data.
About 6.2% of MOT tests recorded on the Riley Merlin in DVSA data end in a failure. The same handful of items account for most of them.
Its most common failure is fuel system, which makes up 40.0% of the Riley Merlin's failures, followed by fuel system, brakes. Each item below links to the part that resolves it. Confirm the exact fitment against your registration or VIN before buying, and have safety-critical work done by a competent mechanic.
What it fails on, and why
Fuel-system failures are leaks or an insecure filler cap.
Brake failures cover worn pads and discs, an imbalance between wheels, corroded or scored discs, or a binding caliper. Braking efficiency is measured on a rolling road, so a spongy or pulling brake shows up as a low reading.
The parts that fix each
If your car has just failed, you have 10 working days to fix the items and get a free partial retest. These are the usual parts; confirm the exact fitment against your registration or VIN before buying.
Other models
Sources: DVSA MOT History API: MOT test results and defect data ยท DVSA MOT testing data for Great Britain