MG B
From 3,563 MOT tests. Above average for its class.
Common MOT failure categories
Pass rate by registration year
What goes wrong?
The most common MOT failure reasons are windscreen washers not working or not providing sufficient fluid to clear the windscreen, steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc and emissions levels exceed default limits. The top issue, windscreen washers not working or not providing sufficient fluid to clear the windscreen, caused 98 failures in 2024. If you need repairs before retesting, sites like BookMyGarage let you compare local prices.
| windscreen washers not working or not providing sufficient fluid to clear the windscreen | 98 |
| steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc | 73 |
| emissions levels exceed default limits | 72 |
| the aim of a headlamp is not within limits laid down in the requirements | 62 |
| a lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning | 61 |
| 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. | 55 |
| a headlamp or light source missing, inoperative or more than ½ not functioning in the case of led | 54 |
| audible warning inoperative | 42 |
| significant brake effort recorded with no brake applied indicating a binding brake | 40 |
| wiper blade missing or obviously not clearing the windscreen | 31 |
How serious are these failures?
Not all MOT failures are equal. Only 16.2% of B failures are serious (safety or roadside), below the 44.4% average. When this car fails its MOT, it's more likely to be lights, wipers, or emissions than something dangerous. When it does fail, the average repair bill is around £66.
By registration year
| Year | Pass rate | Top failures |
|---|---|---|
| 1981 | 86.2% | emissions levels exceed default limits, the aim of a headlamp is not within limits laid down in the requirements |
| 1980 | 82% | emissions levels exceed default limits, windscreen washers not working or not providing sufficient fluid to clear the windscreen |
| 1979 | 84.2% | emissions levels exceed default limits, windscreen washers not working or not providing sufficient fluid to clear the windscreen |
| 1978 | 87% | emissions levels exceed default limits, body, cab or chassis excessively corroded at a mounting point |
12 earlier years
| 1977 | 82.6% | emissions levels exceed default limits, the strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired |
| 1976 | 74.1% | a headlamp or light source missing, inoperative or more than ½ not functioning in the case of led, emissions levels exceed default limits |
| 1975 | 85.5% | braking effort inadequate at a wheel, the aim of a headlamp is not within limits laid down in the requirements |
| 1974 | 85.1% | steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, significant brake effort recorded with no brake applied indicating a binding brake |
| 1973 | 84.9% | windscreen washers not working or not providing sufficient fluid to clear the windscreen, 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. |
| 1972 | 86.5% | steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, 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. |
| 1971 | 84% | windscreen washers not working or not providing sufficient fluid to clear the windscreen, a lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning |
| 1970 | 81.2% | steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, the aim of a headlamp is not within limits laid down in the requirements |
| 1969 | 85.4% | windscreen washers not working or not providing sufficient fluid to clear the windscreen, a stop lamp not showing a steady red light or has significantly reduced light intensity |
| 1968 | 89.2% | a headlamp or light source missing, inoperative or more than ½ not functioning in the case of led, a suspension pin, bush or joint excessively worn |
| 1967 | 88.1% | windscreen washers not working or not providing sufficient fluid to clear the windscreen, 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. |
| 1966 | 85.1% | 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., windscreen washers not working or not providing sufficient fluid to clear the windscreen |
Typical mileage
Half of all Bs tested had between 10,029 and 58,566 miles on the clock. Relatively low mileage overall. Many are still fairly young.
At 38,962 median miles, the B has 0.039 failures per 10,000 miles driven.
Other MG models
| MG Zs | 81.9% |
| MG 3 | 79.4% |
| MG Zs Exclusive Ev | 89.5% |
| MG Tf | 75% |
| MG Mgf | 72.8% |
Common questions
What is the MG B MOT pass rate?
The MG B has a 84.8% MOT pass rate based on 3,563 real MOT tests. This is above the national average.
What are common MOT failures on a MG B?
The most common MOT failure on the MG B is windscreen washers not working or not providing sufficient fluid to clear the windscreen, which caused 98 failures. Other common issues include steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc.
What is the typical mileage of a MG B at MOT?
The median mileage at MOT for a MG B is 38,962 miles. The middle 50% of vehicles tested have between 10,029 and 58,566 miles.
Buying a used B?
Start with the free tools. Look up the specific vehicle's MOT history on GOV.UK The mileage at each test will show if it's been wound back, and the advisory history tells you what's wearing. Cross-reference that against the typical failures above to see if anything looks unusual for this model.
The free data won't tell you about outstanding finance, theft markers, or write-off history. For that, you need a vehicle history check This is especially important on a private sale where you have fewer legal protections.
With a 84.8% pass rate and an average repair bill of £66 when things go wrong, budget accordingly.
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MOT data from DVSA anonymised test results, 2024 test year. Fleet data from DfT vehicle licensing statistics. Crown copyright, OGL v3.0. MOT pass rates are statistical summaries of test outcomes, not assessments of individual vehicle safety or condition. Always inspect a vehicle and check its full MOT history before purchasing. See terms of use.