You just did a brake job and the brakes are making noise. Frustrating - but usually fixable. New-brake noise comes from a short list of causes, and most trace back to a step in the install. Here is how to sort it out.
Normal break-in noise
Some light noise in the first hundred miles is normal while new pads bed in against the rotor. If the pads were not bedded in with a proper series of moderate stops, they can be noisier at first - see our bedding guide. Proper break-in often quiets things down on its own.
Missing or reused hardware
This is the most common cause of squeal after a brake job. The clips and shims that locate the pad must be fresh - old, rusty hardware lets the pad vibrate and ring. Always install a new brake hardware kit with new pads. Reusing worn hardware is the number one reason new brakes squeak.
No grease on the contact points
The pad contact points and caliper slide pins need a thin film of high-temp brake grease so pads move freely and do not vibrate - but never on the friction surface. See where to apply brake grease.
Glazed or contaminated surfaces
Grease, oil, or fingerprints on the rotor face or pad friction material can cause noise and reduced bite. New rotors ship with a protective oil that must be cleaned off with brake cleaner before install. If a pad got contaminated, it may need replacing.
Grinding is different
Light squeal during break-in is common; grinding is not. If new brakes grind, stop and re-check the install - a pad installed wrong, debris caught in the caliper, or a backing plate contacting the rotor. When in doubt, re-check the work or see a professional. Start with the correct pads for your vehicle and fresh hardware to avoid noise in the first place.