Squeaky brakes are primarily caused by several factors: worn or thinning brake pads, debris or dust caught between the brake pads and rotors, moisture or rust on the rotors, loose or damaged hardware, insufficient lubrication, and sometimes poor brake pad quality. A common cause is worn brake pads with a metal wear indicator designed to make a squealing noise when pads need replacing. Moisture can cause a thin rust layer on rotors that squeaks until worn off by braking. Debris like dirt or small stones can also cause noise, which usually resolves after cleaning or driving. Loose components or lack of lubrication can cause vibrations leading to squeals. In expensive or prolonged cases, warped or glazed pads and rotors can cause persistent squeaking, requiring professional inspection and repair.

Actionable advice includes checking brake pad thickness regularly, cleaning the brake assembly to remove debris, ensuring proper lubrication of hardware, and having a mechanic inspect the brakes if the noise persists to avoid damage to rotors or brake failure. Using higher-quality brake pads can also reduce squeaking caused by metal flakes in cheaper pads. Weather conditions often cause temporary squeaks that stop after driving.