Brake MOT failures
Brakes are one of the top five failure areas and, with tyres, cause most of the dangerous defects found at MOT.
Checked against the MOT inspection manual and GOV.UK guidance · Updated November 2026
How brakes are tested
Most cars are tested on a roller brake tester: each axle sits on rollers that drive the wheels while the tester presses the pedal. The machine measures the braking force at each wheel. From that it calculates:
- Service brake efficiency – total braking force as a percentage of the vehicle's weight. For most cars first used from 1 September 2010 the minimum is 58%; for older cars it's 50%.
- Parking brake efficiency – at least 16% for most cars.
- Imbalance – the difference between the left and right wheel on the same axle. More than 30% is a fail.
- Binding and fluctuation – a wheel that drags with the brake off, or force that pulses (warped disc or oval drum).
The tester also inspects discs, pads, drums, pipes, hoses, the master cylinder, the brake fluid level and warning lamps, the ABS and electronic stability control lamps, and electronic parking brakes.
Common brake failures
| Defect found | Usual category |
|---|---|
| Service brake efficiency below minimum | Major |
| Service brake efficiency below 50% of the minimum | Dangerous |
| Brake imbalance over 30% on an axle | Major |
| Parking brake efficiency below 16% | Major |
| Brake pad or shoe lining under 1.5mm, or wear indicator lamp on | Major |
| Brake pad or shoe missing or incorrectly fitted | Dangerous |
| Brake disc or drum significantly worn, cracked or insecure | Major / Dangerous |
| Brake pipe excessively corroded | Major |
| Brake pipe or hose leaking | Dangerous |
| Brake hose bulging under pressure or damaged | Major |
| ABS or ESC warning lamp on | Major |
| Brake fluid warning lamp on or fluid below MIN | Major |
| Electronic parking brake malfunction warning | Major |
Why imbalance fails so many cars
Imbalance usually comes from one side not working properly: a seized caliper slider pin, a stuck piston, a contaminated pad or a rear drum brake with a seized adjuster. The car may pull to one side under braking. The fix is often a caliper service or a new caliper rather than just pads.
Corroded brake pipes
Steel brake pipes run under the car and rust from the outside. Once they're pitted or scaled, they fail. Pipes are a common failure on cars over 10 years old and the repair can be cheap or expensive depending on access – a single section by the wheel is quick; pipes running over the fuel tank or rear subframe can mean several hours' labour.
Discs on low-mileage and electric cars
Cars used for short trips, and electric and hybrid cars which do much of their braking regeneratively, often fail on corroded discs – the friction surface rusts because the brakes are rarely used hard. See our EV and hybrid guide.
Repair costs
| Repair | Typical cost | DIY? |
|---|---|---|
| Front brake pads | £70–£150 | Yes, with care |
| Front discs and pads | £150–£350 | Yes, with care |
| Rear discs and pads | £150–£350 | Electronic handbrake may need a tool |
| Rear drum shoes and service | £100–£200 | Often |
| Brake caliper (each, reconditioned) | £100–£250 | Often – needs bleeding |
| Brake hose (each) | £50–£110 | Yes – needs bleeding |
| Brake pipe section | £60–£150 | Possible |
| Full brake pipe replacement | £250–£600 | Specialist |
| Handbrake cable | £60–£160 | Often |
| ABS sensor | £80–£200 | Often – plus diagnosis |
| ABS pump/module | £400–£1,200 | No |
Typical UK independent garage prices including parts, labour and VAT, 2026. Main dealers and premium/4x4 vehicles cost more.