Why are my brakes squealing?

Brake squeal is most often the built-in wear indicator on your brake pads telling you they're worn down to about 3mm and need replacement. Other causes include glazed pads, rust on the rotors, or missing anti-rattle shims.

Cost range: $100–$400. Severity: medium. Safe to drive? Drivable short-term, but plan to replace pads within 1–2 weeks. If squealing turns into grinding, stop driving — the pads are gone and you're cutting into the rotor.

Most likely causes

1. Worn brake pads (wear indicator) — A small metal tab on the pad scrapes the rotor when the pad is ~3mm thick, producing a high-pitched squeal that goes away when you brake. ($100–$300 per axle, common)
2. Glazed pads or rotors — Excessive heat hardens the pad surface so it doesn't bite. Usually fixed by bedding-in new pads or light rotor resurfacing. ($0–$200, common)
3. Surface rust on rotors — Common after rain or sitting overnight. Squeal disappears within the first few stops. ($0, common)
4. Missing or worn anti-rattle shims — Shims dampen vibration between pad and caliper. When missing, pads vibrate audibly. ($20–$80, less common)