MOT performance

MOT failure “Brake discs: significantly and obviously worn”: how common it is and which cars get it

“Brake discs: significantly and obviously worn” (major defect, brakes) was recorded as a failure on 0.60% of UK MOT tests in 2023–2024: 395,728 tests, the number 28 most common failure item. It is 3.1 times as common at 10 years old (0.78%) as at 3 (0.25%). It is most common at 13 years old (0.84% of tests).

395,728 tests with this failure, 2023–2024

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At a glance

“Brake discs: significantly and obviously worn” at a glance
Figure	Value	Basis
Share of MOT tests	0.60%	395,728 tests, 2023–2024
Rank among failure items	#28	by number of tests
Most common at	13 years old	0.84% of tests at that age
Models compared	385	models with enough tests

How it changes with age

Share of MOT tests failing on “Brake discs: significantly and obviously worn” by age
Age at test	Share of tests
3 years	0.25%
5 years	0.39%
7 years	0.56%
10 years	0.78%
12 years	0.83%
13 years	0.84%
15 years	0.82%
18 years	0.74%
20 years	0.65%

By fuel

Diesel: 0.69% of tests; Petrol: 0.57% of tests; Hybrid: 0.21% of tests; Electric: 0.17% of tests. Fuel groups differ in age and mileage, so these raw shares are not like-for-like; the model tables below are.

Models that fail on it most often

Relative to cars of the same age and fuel (1.00 = national rate for this item). Only models with enough tests for the difference to be clear are ranked.

Models failing most often on “Brake discs: significantly and obviously worn”
Model	Tests	Failed on it	vs similar cars
Skoda Kamiq	24,109	1.16%	+387%
Citroen C3 Aircross	54,618	1.50%	+384%
Vauxhall Crossland	118,672	1.33%	+354%
MG HS	15,467	0.89%	+322%
Skoda Scala	12,748	1.00%	+301%
MG ZS	71,594	0.96%	+289%
DS DS 3	68,070	1.52%	+212%
Renault Megane	227,348	2.22%	+201%
Citroen DS3	146,860	2.26%	+197%
Volkswagen T-Cross	38,196	0.71%	+183%

Models that fail on it least often

Models failing least often on “Brake discs: significantly and obviously worn”
Model	Tests	Failed on it	vs similar cars
Fiat Swift	15,103	0.01%	-97%
Aston Martin Vantage	15,831	0.02%	-97%
Fiat Auto Trail	20,441	0.02%	-96%
BMW 6 Series	10,465	0.04%	-93%
Honda S2000	10,058	0.05%	-92%
BMW 640	20,209	0.06%	-91%
Porsche Macan	56,741	0.04%	-90%
Jaguar I-Pace	30,624	0.01%	-88%
Jaguar F-Type	28,642	0.07%	-87%
Jaguar Xkr	17,216	0.10%	-84%

Makes that stand out on this failure

Makes whose cars record this failure clearly more or less often than comparable cars (same age, mileage and fuel):

DS · 2.86× comparable cars
MG · 2.28× comparable cars

About this defect

The wording is DVSA's, from the MOT inspection manual. A high ratio for a model reflects its MOT record, which depends on maintenance and use as well as design. For one car, its own MOT history shows whether this has come up before.

Other common brakes failures

Brake pads: less than 1.5 mm thick · 1.89% of tests
Rbt (sp): efficiency below requirements · 1.11% of tests
Service brake performance: excessively binding · 0.72% of tests
Rigid brake pipes: excessively corroded · 0.66% of tests
Parking brake performance: inoperative on one side · 0.52% of tests
Anti-lock braking system: warning lamp indicates an ABS fault · 0.41% of tests
Service brake performance: excessively fluctuating · 0.31% of tests
Service brake imbalance: across an axle · 0.30% of tests

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UK number plate or 17-character VIN

About this data. These are MOT test results, not a measure of mechanical reliability: a car's MOT outcome reflects its condition on the day, which depends on how it has been maintained and driven as well as how it was built. Figures cover class 4 vehicles (cars and light vans), normal tests only (retests excluded), outcomes pass, fail and pass after rectification at the station; vehicles at least 2.5 years old at test. Tests from 2023-01-01 to 2024-12-30. “Compared with similar cars” means compared with the national rate for cars of the same age, mileage band and fuel. Contains public sector information licensed under the Open Government Licence v3.0. Makes and models are matched to 73 Auto's vehicle catalogue; tests that can't be matched are left out rather than guessed. See how the MOT figures are produced.