Brake pads, discs and fluid: what the MOT checks, and when to act before winter roads

The short answer

The MOT tester checks four things about your brakes: how much is left of the pads and discs, whether the fluid is at the right level and clean, whether the pipes and hoses are sound, and how hard and how evenly the car actually stops on a roller brake tester. The manual grades every finding as minor, major or dangerous. A pad worn to its wear indicator is major; a pad worn below 1.5mm is dangerous. A disc that is significantly and obviously worn is major. Brake fluid a little below the minimum mark is minor; fluid you cannot see at all is dangerous.

Those are the test's lines. Yours should sit earlier. The Highway Code says the gap to the car in front should be at least doubled on wet roads and can need to be up to ten times greater on ice, and the brakes that have to deliver that are the ones with the pads, discs and fluid the tester last saw up to a year ago.

Pads and discs: what counts as worn

Section 1.1.13 of the MOT inspection manual's brake section covers linings and pads. A pad worn down to its wear indicator is a major defect and the car fails. A pad worn below 1.5mm is dangerous, which means the car must not be driven away from the test until it is fixed. A pad contaminated with oil or grease is major; one missing or incorrectly mounted is dangerous. The manual also says an illuminated pad wear warning light is not in itself a reason for failure: the tester looks at the pad, not the lamp.

Section 1.1.14 covers discs and drums. A disc significantly and obviously worn is major; one insecure, fractured or otherwise likely to fail is dangerous. Wear below the manufacturer's own recommended limit is not by itself a reason to reject, so a disc can be past the point your handbook would replace it and still pass. A pass with a brake advisory is a job to book, not a reason to relax.

Fluid, pipes and hoses

The fluid check is simpler than most people expect. The tester looks at the level through a transparent reservoir and does not remove the cap. Fluid below the minimum mark is minor; significantly below it is major; fluid not visible at all is dangerous. Fluid that is clearly contaminated is major. The manual does not set a change interval for brake fluid; your handbook does, and because fluid absorbs moisture over time, the interval is usually by age rather than mileage.

Rigid brake pipes run the length of the car and corrode where the salt sits. A pipe damaged or excessively corroded is major, and one leaking on a hydraulic system, or at imminent risk of failure, is dangerous. Flexible hoses at each wheel are judged the same way: excessively damaged, chafed, twisted or stretched is major; damaged and likely to fail is dangerous. A torch in the wheel arch will not show you these fully; a garage with the car on a ramp will.

How stopping power is measured

The tester puts the car on a roller brake tester, which the manual calls the primary brake tester and which must be used unless the vehicle is unsuitable, in which case a decelerometer is used on the road. The machine measures the braking effort at each wheel. Under section 1.2.1, braking effort inadequate at a wheel is major and effort not recording at a wheel is dangerous. Imbalance matters too: where one wheel on an axle gives less than 70% of the effort of the other it is major, and less than 50% on a steered axle is dangerous. A brake that binds when the pedal is released is major.

Section 1.2.2 then sets the overall efficiency. For a car first used on or after 1 September 2010 the service brake must reach 58% efficiency; below that is major and less than half the required value is dangerous. You cannot measure this at home, but you can notice the signs it has changed: a longer pedal, a pull to one side, a judder, a new noise.

What to do before the wet and icy months

1. Read the last MOT. Run the registration through the free GOV.UK MOT history service. A brake advisory from the last test, on pads, discs or pipes, is a job that has been waiting up to a year.
2. Look at the pads through the wheel. On most alloys you can see the outer pad against the disc. Thin, glazed or uneven is the time to have it measured. If the car has a wear warning lamp, treat it as the earliest signal, not the last.
3. Check the fluid. Level between the marks, colour pale and clear. Dark fluid or a level that has dropped since you last looked is a conversation with a garage.
4. Feel for the signs. A soft or long pedal, a pull to one side, a pulse through the pedal, a grinding noise. Any of these on a dry road will be worse on a wet one.
5. After deep water, test the brakes. Highway Code rule 121 says to test them at the first safe opportunity by pushing gently on the pedal, and if they are not fully effective, to apply light pressure while driving slowly to dry them out.
6. Double the gap. Rule 126 is the one that costs nothing: the gap to the car in front at least doubled on wet roads, and far more on ice. Rule 120 adds that a car with anti-lock brakes does not stop in a shorter distance; in an emergency, press firmly and keep pressing.

What this does not mean

This article carries no figures from our MOT data; it is the brake section of the inspection manual and three rules of the Highway Code, as read on GOV.UK today. The manual's limits are the point at which a tester must fail the car, not the point at which a careful owner should act, and it does not tell you how long pads or discs last on your car, because that depends on the car, the roads and the driver. Your handbook sets the service intervals; the test sets the floor. A pass, even a clean one, says the brakes met the standard on the day of the test, not that they will next month.

Sources and method

This article contains no MOT statistics. Its content is section 1 of the MOT inspection manual for cars and light vehicles and rules 120, 121 and 126 of the Highway Code, as read on GOV.UK on 6 November 2026, with the Met Office UK forecast issued at 16:00 on 5 November 2026 for the weather line. The MOT data on brake fails and advisories by car age is in the two linked articles.

• GOV.UK: MOT inspection manual, section 1, brakes
• GOV.UK: The Highway Code, general rules (rules 120, 121 and 126)
• GOV.UK: Check the MOT history of a vehicle
• Met Office: UK weather forecast

This article is general information drawn from published test records. It is not professional, mechanical or legal advice, and an MOT pass or a clean MOT history does not guarantee that a car is roadworthy today. If you are unsure about a car, have it inspected by a qualified mechanic. You can check any vehicle's MOT history free on the official GOV.UK MOT history service.