Why does my air disc brake make a sharp noise during braking?

2025-11-09 16:00:43

This type of noise typically originates from vibration between the brake pads and the rotor. Common causes include:

• Worn-out brake pads contacting the wear indicator: Many pads have built-in wear indicators. When the pad material wears down to a critical level, a small metal shim (the indicator) makes contact with the rotor, producing a high-frequency squeal to signal that replacement is needed.

• Glazed or contaminated brake pads: High temperatures from braking can cause the pad surface to harden or become "glazed." Alternatively, foreign materials like embedded metal particles can create hard spots. Both conditions lead to noisy friction when contacting the rotor.

• Component vibration: If anti-rattle clips (shims) are incorrectly installed, missing, or if the caliper slide pins are insufficiently lubricated, it can allow the brake pads to vibrate within the caliper assembly, generating noise.