MOT defect file
Brake pads wearing thin
Last updated
Quick answer
Friction material on the pads is close to its limit. Straightforward to replace, and cheaper if done before the discs are damaged.
- Typical cost
- £90–£200
- DIY viability
- Possible with care
What you might notice
- A high-pitched squeal under light braking that goes quiet when you press harder — that is the wear indicator doing its job
- Grinding or a metallic rasp, which means the friction material has already gone and the backing plate is on the disc
- The pedal sitting lower than it used to, or needing a firmer push for the same result
- Frequently nothing — pads sit behind the wheel and most drivers never see them between services
What causes it
- Ordinary use: front pads on a typical car last somewhere between 25,000 and 40,000 miles, less on a heavy car or in town driving
- A seized calliper slide pin holding one pad against the disc, which wears it out at two or three times the normal rate
- Stop-start urban mileage or regular towing, both of which put far more heat and load through the front axle
- Cheap pads with a soft compound that wears quickly and glazes under heat
Advisory or failure?
Pads that are wearing but still have usable material left are recorded as an advisory, and that is the point at which replacing them is cheapest. It becomes a major defect once the friction material is below 1.5mm, or below the manufacturer's own minimum where that figure is higher. Pads that are missing, insecurely mounted, contaminated with oil or brake fluid, or worn so far that the rivets or backing plate are contacting the disc are graded dangerous.
Can you fix it yourself?
Possible with care
Pads alone are among the more approachable jobs, but this is the braking system and it deserves the right kit: axle stands rather than a jack, a torque wrench for the carrier and guide bolts, and copper grease on the pad backs and slides but never on the friction face. Rear pistons usually have to be wound back rather than pushed, and any car with an electronic parking brake must be put into service mode with a diagnostic tool first — forcing the piston back against the motor will wreck the actuator. Bed the new pads in gently for the first hundred miles.
What it costs
Pads for one axle are usually £25 to £60 in parts on a mainstream car with about an hour of labour, which puts most jobs near the bottom of the band. You reach the top when the discs have been scored and have to go at the same time, when a seized calliper or slide pin needs freeing, or when a rear electronic parking brake has to be retracted and recalibrated with a diagnostic tool.
What happens if you ignore it
Pads do not stop working overnight, but once the friction material has gone the steel backing plate cuts into the disc, and a £90 pad change becomes £250 for pads and discs. Braking effort falls away as it worsens, so the car will eventually fail the efficiency test with nothing else wrong with it. Driving on metal-to-metal brakes is using a vehicle in a dangerous condition, which carries a fine and penalty points quite apart from the MOT.
Common questions
- At what thickness do brake pads fail the MOT?
- Pads become a major defect and a failure once the friction material is below 1.5mm, or below the manufacturer's own minimum where that figure is higher. Pads that still have usable material left are recorded as an advisory instead. Missing or insecure pads, ones contaminated with oil or brake fluid, and pads worn down to the rivets or backing plate are graded dangerous.
- Why are my brakes squealing when I brake gently?
- A high-pitched squeal under light braking that goes quiet when you press harder is normally the wear indicator, a small metal tab designed to touch the disc and make that noise when the pad is nearly finished. A deeper grinding or metallic rasp is a different and more urgent noise: the friction material has gone and the backing plate is on the disc.
- How long do brake pads last?
- Front pads on a typical car last somewhere between 25,000 and 40,000 miles, and rears usually last longer. A heavy car, stop-start town mileage and regular towing all shorten that considerably. A seized calliper slide pin holding one pad against the disc will wear it out at two or three times the normal rate.
- Can I change brake pads myself?
- It is one of the more approachable jobs, but it is the braking system, so use axle stands rather than a jack and a torque wrench on the carrier and guide bolts. Rear pistons usually have to be wound back rather than pushed, and a car with an electronic parking brake must be put into service mode with a diagnostic tool first or you will wreck the actuator.
- What happens if I keep driving on worn brake pads?
- Once the friction material has gone, the steel backing plate cuts into the disc, and a £90 pad change becomes around £250 for pads and discs. Braking effort falls away as it worsens, so the car can fail the efficiency test with nothing else wrong with it. Driving on metal-to-metal brakes is using a vehicle in a dangerous condition, which carries a fine and penalty points.
This is general guidance, not a diagnosis. The severity DVSA records depends on the specific fault found, so the same item can appear as an advisory on one test and a failure on another. Ask a qualified tester or mechanic to inspect the vehicle.
Has this been recorded on your car?
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