Why Are My Brakes Squealing?
A high-pitched squeal from your brakes is hard to ignore — and in most cases, it's your car's way of telling you something needs attention. The good news is that brake squealing doesn't always mean an emergency, but it does mean you shouldn't ignore it for long.
The Most Common Cause: Worn Brake Pad Indicators
Modern brake pads are fitted with a small metal wear indicator — a thin strip of steel that's designed to contact the rotor once the friction material wears down to a safe minimum. When it does, it creates a deliberate squealing sound. Think of it as your car's built-in reminder to book a service.
If you're hearing a squeal every time you brake, especially after the car has warmed up, worn pad indicators are the most likely culprit. At this stage you typically still have a small amount of pad material left, but you're in the warning zone.
Dust and Debris on the Rotor
A light film of surface rust can build up on brake rotors overnight or after rain. The first few stops of the day often produce a brief squeal or scraping noise as the pads clear the rust off. This is normal and usually disappears within a kilometre or two.
Similarly, small pieces of grit, sand, or debris occasionally lodge between the pad and rotor. This can cause a squeal that comes and goes.
Glazed Pads or Rotors
If brakes have been overheated — such as on a long downhill stretch with continuous braking — the friction surface can harden and glaze over. Glazed pads produce a consistent squeal and also reduce braking performance. This usually requires resurfacing or replacing the rotors.
Cheap or Incompatible Brake Pads
Lower-quality or aftermarket brake pads can squeal simply because their friction compound isn't a good match for your rotors. If your brakes were recently serviced and squealing started afterwards, the pad choice may be the issue.
Is It Safe to Drive?
If the squeal is intermittent and disappears after the first few stops, it's likely harmless. If it happens every time you brake — especially if it's getting louder or you can feel it through the pedal — get it checked promptly. Ignoring wear indicators long enough means the metal backing plate contacts the rotor directly, which causes grinding and can quickly damage expensive components.
WoF Implications
A brake inspection is part of every Warrant of Fitness check. Excessively worn brake pads will fail a WoF, so if you're coming up for a WoF and hearing squealing, get the pads checked first.
What to Tell Your Mechanic
Note when the squealing happens — cold or warm, light braking or hard braking, front or rear — and whether it's getting worse. This helps narrow down the cause quickly.