MG B: MOT pass rate and reliability data

The MG B passes its MOT first time more often than the average UK car, by 7 percentage points. These figures come from the DVSA's full year of anonymised MOT results, covering 2,527 individual MG B tests. Nothing here is an estimate or a survey.

The numbers

What this means if you are buying one

A 83.7% first-time pass rate means roughly 16 in every 100 MG Bs presented for MOT fail on the first attempt. That is better than average, so a well-kept example is a reasonably safe used buy. The average MG B tested had covered 43,598 miles and was built around 1976.

What this means at salvage auction

Pass rate is a proxy for what a car costs to keep on the road. The MG B sits 7 points above the national average, ranked 1,314 of 2,005 models. On one bought as repairable salvage, the mechanical side is less likely to spring surprises, so your repair estimate should hold up reasonably well.

Before you bid: run the lot through the analyzer, check the car's own record, check the mileage, decode the VIN, and if it carries a marker use the write-off value calculator. Or compare it against another model.

Looking at a specific MG B rather than the model in general? The free check covers its MOT and mileage history, and the full HPI report confirms the insurance write-off category, outstanding finance and whether it is recorded stolen, from licensed data for 5 credits. Already own one that has been damaged? Work out whether fixing it beats selling it with the repair or scrap calculator, and see recorded closing bids for damaged MG Bs at UK salvage auction.

Most common MOT failures on a MG B

1. Stop lamps all missing or inoperative, 0.9% of tests (11.06x the national rate for this defect)
2. Emissions levels exceed default limits, 3.1% of tests (8.63x the national rate for this defect)
3. Audible warning inoperative, 1.6% of tests (5.63x the national rate for this defect)
4. Brakes imbalance across an axle such that the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle., 2% of tests (3.87x the national rate for this defect)
5. Steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, 2.7% of tests (3.62x the national rate for this defect)
6. Windscreen washers not working or not providing sufficient fluid to clear the windscreen, 3.5% of tests (2.05x the national rate for this defect)
7. A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 1.3% of tests (1.94x the national rate for this defect)
8. A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED, 1.9% of tests (1.59x the national rate for this defect)
9. Significant brake effort recorded with no brake applied indicating a binding brake, 1.5% of tests (1.49x the national rate for this defect)
10. The aim of a headlamp is not within limits laid down in the requirements, 2.5% of tests

From 2,521 DVSA-tracked MG B tests, 2024. DVSA testers marked 3.49% of these flagged MG B defects as "dangerous", meaning the tester judged the car unsafe to drive away, against 5.11% nationally.

Most common MOT advisories on a MG B

An advisory doesn't fail the car - the tester flags it as worth watching, but it still passes. A different list from the failures above: what testers are noting on a MG B before it actually fails on it.

1. A wheel bearing with excessive play, 5.6% of tests (8.56x the national rate for this advisory)
2. Brakes imbalance across an axle such that the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle., 1.2% of tests (3.61x the national rate for this advisory), also fails
3. A wheel bearing excessively rough, 1.1% of tests (2.88x the national rate for this advisory)
4. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 14.8% of tests (2.66x the national rate for this advisory)
5. Significant brake effort recorded with no brake applied indicating a binding brake, 2.6% of tests (1.29x the national rate for this advisory), also fails
6. A suspension pin, bush or joint excessively worn, 8.4% of tests
7. A tyre seriously damaged, 4.3% of tests
8. Tyre tread depth not in accordance with the requirements, 2.7% of tests
9. Exhaust system leaking or insecure, 2.1% of tests
10. Brake pipe damaged or excessively corroded, 2.1% of tests

From 2,521 DVSA-tracked MG B tests, 2024.

Other MG models

• MG Zs - 81.4%
• MG 3 - 80.1%
• MG Zs Exclusive Ev - 90.6%
• MG Tf - 72.4%
• MG Mgf - 69.6%
• MG 5 Exclusive - 91.6%
• MG Zs Exclusive Vti-Tech - 90.3%
• MG Hs Exclusive S-A - 91.9%

Models with a similar pass rate

• Isuzu D-Max Utility - 83.8%
• Ford Transit Custom 300limitd Eblue - 83.7%
• Mercedes-Benz Gl - 83.7%
• DS Ds7 - 83.7%
• Ford Transit 290 Trend Ecoblue - 83.7%
• Ford Transit Custom 280limitd Eblue - 83.6%

If this car is a salvage or write-off

• What does Cat N mean? Category N explained
• What does Cat S mean? Category S explained
• Cat S vs Cat N: the real differences
• Do you need an HPI check on a car you know is a write-off?

Embed this data

Run a site about the MG B? Embed the real DVSA pass-rate badge free, linked back to this page.

<a href="https://www.salvageprophet.co.uk/mot/mg-b"><img src="https://www.salvageprophet.co.uk/badge/mg-b.svg" width="340" height="92" alt="MG B MOT Pass Rate: 83.7% - Salvage Prophet"></a>

Run a garage or parts site? Embed the MG B's top real failure reason instead, linked back here.

<a href="https://www.salvageprophet.co.uk/mot/mg-b"><img src="https://www.salvageprophet.co.uk/badge/failure/mg-b.svg" width="340" height="106" alt="MG B most common MOT failure: Stop lamps all missing or inoperative (0.9% of tests) - Salvage Prophet"></a>

All 2,005 models ranked by MOT pass rate