Brakes and steering
Noise when braking: what a squeal or a metallic grinding means
A high-pitched squeal when braking is usually the pad wear indicator or glazed pads. A deep metallic grinding means the pad has worn down to the metal and is damaging the disc: it needs checking now.
See a garage soonBrakes and steering
Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Carefully, and only as far as the garage. With a light squeal, have the brakes checked soon. With metallic grinding, knocks, or if the car brakes less or pulls to one side, drive as little as possible and leave plenty of distance, or call for assistance: braking can get worse suddenly.
A careful, general answer: only someone who inspects the car can say whether it is safe to drive. When in doubt, stop somewhere safe and call for assistance.
Most likely causes
- Worn pads: many have a metal tab that squeals when little friction material is left.
- Glazed pads or dust: after hard braking or a long time parked, they squeal without being worn.
- Pad worn through: metal-on-disc grinding: the disc gets scored and brakes worse.
- Rust after rain or days parked: a scraping for the first few stops that soon goes away; it is normal.
- Caliper or slide pins: a caliper that does not slide freely makes noise and wears the pad unevenly.
Listed from more to less common in general; on your car they may be different. A fault-code reading and a check at the garage confirm which one it is.
To understand it better: How often should you run diagnostics on your car? Can I diagnose my car myself?
Car system: Brakes, ABS and ESC
What you can check yourself
Notice whether the noise goes away after a few stops (rust) or is always there.
Look at the discs through the wheel: deep grooves or a pronounced lip mean wear.
Check whether the car pulls when braking or one wheel gets much hotter than the others, without touching it.
Check when the pads were last changed.
Safe checks only: with the engine off and cold whenever you look under the hood, without taking anything apart and without touching hot or moving parts.
Related fault codes
This symptom is usually mechanical and does not always store a generic fault code. Even so, reading the faults of every control unit helps to rule out other problems and to reach the garage with data.
How the ECO-LITE helps diagnose it
Plugged into the OBD socket, the ECO-LITE reads the fault codes of the control units that answer, with the freeze-frame data captured when the fault happened, and shows live data on your phone or computer. With your permission, your garage can see them remotely before you bring the car in.
What to look at here: this noise is mechanical; reading the brake control unit rules out other ABS faults or the wear sensor on cars that have one.
Frequently asked questions
Is it normal for brakes to squeal in the morning?
A scrape or squeal for the first few stops after rain or damp is usually surface rust and goes away. If it lasts, have them checked.
Are discs and pads always changed together?
Not always: it depends on the thickness and condition of the disc. If the pad reached the metal, usually yes.
Does this noise store a fault code?
Usually not. Some cars with a wear sensor show a light or store a service message.
Keep reading
- Brakes, ABS and ESC: how they work and what fails
- Vibration when braking: why the steering wheel or pedal shakes
- Red brake warning light on: what it means and what to do
- Soft, long or sinking brake pedal: what to do
- Car symptoms: what they mean and what to do
- Check engine light on: what to do
- How to read and clear your car's fault codes
- OBD fault codes: what each one means