Brakes make different noises for different reasons, and the type of sound is a strong clue to the cause. Use this quick guide to narrow down what your brakes are telling you - then confirm with an inspection.
High-pitched squeal
A steady squeal, often when you are NOT pressing the brake, usually means the pad wear indicator is contacting the rotor - the pads are getting low. A squeal only when cold or in the morning is often harmless surface rust or pad character. See why brakes squeak.
Grinding
A harsh grinding, especially when you press the pedal, typically means the friction material is gone and metal is contacting the rotor - urgent, because it damages the rotor fast. It can also be debris caught in the brake. See why brakes grind.
Clunk or knock
A clunk when you first apply or release the brakes often points to loose or missing hardware, worn caliper mounting, or a pad moving in the bracket. Fresh hardware usually cures a rattly clunk - see what's in a hardware kit.
Pulsing thud or shudder
A rhythmic thud or a shudder felt through the pedal or steering wheel under braking points to uneven rotors, not a noise problem per se - see brake pedal pulsation and warped rotors.
Steady hum or growl
A hum or growl that changes with speed and shifts when you turn is more likely a wheel bearing than the brakes - see wheel bearing vs brake noise.
Quick reference
- Squeal not braking - worn pads (wear indicator).
- Grind braking - metal on metal, urgent.
- Clunk/rattle - hardware or loose component.
- Pulsing shudder - uneven rotors.
- Hum changing with turns - wheel bearing.
Any grinding, or noise with reduced braking, means inspect before driving. Start with the correct pads for your vehicle and fresh hardware.