The picture
300: middle-of-the-pack on first-time pass
Across 741 MOT tests, the 300 returns 72.7% first-time pass — below the UK fleet average. The single most-logged Major fail is a weak handbrake. Parking brake efficiency less than 50% of the and parking brake inoperative on one side round out the top three. Average tested mileage sits at 104,055, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
Top ten reasons for rejection.
- 01
Parking brake efficiency below minimum requirement
43 occurrences · 5.8% of tests
- 02
Parking brake efficiency less than 50% of the required value
36 occurrences · 4.9% of tests
- 03
Parking brake inoperative on one side
35 occurrences · 4.7% of tests
- 04
A steering ball joint with excessive wear or free play
33 occurrences · 4.5% of tests
- 05
A suspension pin, bush or joint excessively worn
32 occurrences · 4.3% of tests
- 06
A suspension joint dust cover severely deteriorated
32 occurrences · 4.3% of tests
- 07
A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
30 occurrences · 4.0% of tests
- 08
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
30 occurrences · 4.0% of tests
- 09
Brake pipe damaged or excessively corroded
21 occurrences · 2.8% of tests
- 10
A suspension pin, bush or joint excessively worn
20 occurrences · 2.7% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 2 failures
£160–£480
If every one of this 300's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
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Build your own retest budget.
Buying or keeping a 300?
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a 300 and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.