Brake Checks: How They’re Tested in an MOT
You know what stands between you and a potential car accident? Your brakes. That’s why brake performance is such a big focus in your car’s MOT test. But what exactly happens during a brake check, and why is it so important? Let’s talk about brake performance and efficiency tests, explore common reasons for brake-related MOT failures – and share some tips to help you keep your brakes in top condition!
How are brakes tested in an MOT?
The MOT test checks whether your vehicle is safe to drive – and the brake check is one of its most rigorous sections. The brake test evaluates both the performance and the condition of your braking system. Here’s what you can expect.
Visual inspection
The MOT tester will start by examining your brakes. This includes checking for wear and tear on brake pads and brake discs (or drums), as well as looking for leaks or damage to brake lines. They’ll also make sure that the brake lights are working.
Brake efficiency test
This is where things get technical. Using a roller brake tester (or, in some cases, a decelerometer), the tester measures the braking force applied by each wheel. The goal is to make sure your brakes can stop the vehicle efficiently and evenly.
This means checking the balance – whether the braking force is evenly distributed between the left and right sides of the vehicle. If one side is significantly weaker, it could cause the car to pull to one side during braking, which is dangerous. As for efficiency, the combined braking force must meet a minimum standard – usually a percentage of the vehicle’s weight. UK MOT regulations state that the minimum acceptable braking efficiency for a car is usually considered to be 58% (for vehicles first used on or after September 1st, 2010), with a maximum axle imbalance of 30% across the brakes.
Parking brake test
The handbrake (or parking brake) is also tested to check it can hold the vehicle stationary on a steep, 16% gradient (1:6) slope. This is particularly important for manual cars.
ABS and electronic systems
If your vehicle is equipped with an Anti-lock Braking System (ABS) or Electronic Brakeforce Distribution (EBD), these systems will be checked to make sure they’re functioning correctly. Any warning lights related to these systems could result in a failure.
Common reasons for brake-related MOT failures
Brake issues are one of the most common reasons for MOT failures:
Worn brake pads or discs
Over time, brake pads wear down due. If they wear down too much, they won’t be able to generate enough stopping power, leading to a failure. Squeaking or grinding noises when braking are often a sign that your pads need replacing. Discs are much hardier, but they still experience wear – and a failed brake disc can be pretty catastrophic.
Brake fluid leaks
Brake fluid is what makes brakes work when you hit the brake pedal. If there’s a leak in the system, or air bubbles have formed in the system, it can reduce braking efficiency and even cause complete brake failure. Brake fluid can also damage some pad materials. Look out for a spongy feeling or slow returning brake pedal.
Corroded or damaged brake lines
Brake lines can corrode over time, especially in older vehicles. Damaged or corroded lines can leak fluid or even burst under pressure, which is extremely dangerous.
Imbalanced braking
If one side of your braking system is significantly weaker than the other, it can cause the car to pull to one side during braking. This imbalance is often caused by uneven wear, a stuck caliper, or a problem with the brake hydraulics.
Faulty ABS or warning lights
If your ABS or brake warning light is illuminated, it’s an automatic MOT failure. These lights indicate a problem with the braking system that needs to be addressed immediately.
Tips for maintaining your brakes
Keeping your brakes in good condition isn’t just about passing your MOT. Your brakes are your first line of defense on the road – so it’s no surprise that they’re put under the microscope during an MOT test.
- Check Brake Fluid Regularly
- Inspect pads and discs
- Address issues (noise, sponginess or pulling to one side under braking) immediately
- Keep your wheels clean
- Get regular servicing
Your brakes need to be up to the task of keeping you safe – but while the MOT is an important checkpoint, it’s up to you to keep your brakes in good condition year-round.
Book your MOT now
If it’s time for your MOT test, get in touch with us. Send your message to enquiries@onlydomots.co.uk, call us on 023 8064 7180 – or book online.
