Why are my brakes squealing?

A brake squeal is a high-pitched noise, a bit like a whistle, that you hear as you slow down. It is very common and often not dangerous on its own. But one of its causes is a warning built into the pads, so the pattern matters: when it happens, and whether it goes away.

Quick guide:

• Only the first few stops of the day, or after rain or a car wash: almost certainly moisture. Nothing to do.
• Every stop, and slowly getting louder: probably the pad wear indicator. Book a brake check soon.
• Grinding or scraping, or weaker braking: past squealing. Stop driving and read our grinding brakes guide.

Likely causes, most common first

1. Pad wear indicator: the pads are getting thin

   Many pads have a small metal tab that touches the disc when the pad is nearly worn. It squeals on every stop, on purpose, to tell you it is time for new pads. Mazda calls it an intentional design feature. Book new pads soon: left too long, the pad wears through to metal and damages the discs.

   Read the fix guide →

2. Moisture and light surface rust

   Discs are bare iron, so dew, rain or a car wash leaves a thin film of rust. The pads scrape it off in the first few stops, sometimes with a squeal. If it goes away after a few stops, it is harmless.

3. Glazed pads

   Overheating hardens the pad surface until it is smooth and shiny. That causes a squeal and less grip. It often comes from long downhill braking, lots of stop-start traffic or resting a foot on the pedal, and sometimes from a sticking caliper. A garage can often deglaze the pads; if they are badly glazed, they need replacing.

4. Cheap or hard pads

   Budget pads often contain more metal, which can drag on the disc and squeal. Good-quality pads that match your car's specification are usually quieter.

   Read the fix guide →

5. Missing or loose shims and clips

   Shims are thin metal or rubber-backed plates behind the pads that damp vibration. If they are missing, worn or loose after a pad change, the pads can vibrate and squeal. A garage can refit them and grease the contact points correctly.

6. Dust, grit or new pads bedding in

   Road grit trapped between pad and disc can squeal or scrape, often at low speed. New pads can also squeak for a while as they bed in. Both usually clear with normal driving; if not, have it checked.

What it costs to fix

Moisture and bedding-in cost nothing. Fitting shims or cleaning and greasing the pad contact points is usually a quick job. If the wear indicator is squealing, you need new pads.

DIY or garage?

How to prevent it

• Replace pads soon after the wear indicator starts squealing.
• Buy good-quality pads, and make sure shims and clips are refitted at every pad change.
• Brake smoothly and early, and use a lower gear on long descents, to avoid glazing.
• Have the brakes checked at every service.