Squeaking Sound When Braking

A squeaking sound when braking is usually caused by worn brake pads, dust or debris between the pads and discs, or glazed brake components. If the noise is high-pitched and persistent, it likely indicates that the brake pads are nearing the end of their lifespan and should be replaced soon.

1. Worn brake pads – Most modern brake pads have wear indicators that produce a squeal when the material is thin. Ignoring this can lead to metal-on-metal contact, damaging the discs.
2. Dust or debris – Small particles trapped between the pad and disc can cause temporary squeaking. Cleaning the brakes may resolve this.
3. Glazed pads or discs – Overheating can harden the pad surface or leave deposits on the disc, reducing friction efficiency. Light sanding or replacement may be needed.
4. Moisture or rust – After rain or overnight condensation, a light layer of rust can form on discs, causing a brief squeak until it wears off.

If the noise persists after a few braking applications, have a mechanic inspect the system. Delaying repairs can lead to costly damage. For electric vehicles like the Tesla Model 3, regenerative braking may reduce pad wear, but traditional brakes still require maintenance.

Reasons for squeaking sound when braking:

1. Use of low-quality or overly hard brake pads, or incorrectly installed or mismatched brake pads: If low-quality or overly hard brake pads are used, the friction between the brake pads and brake discs will produce a squeaking sound when braking. Therefore, it is essential to choose high-quality brake pads when replacing them. Incorrectly installed or mismatched brake pads can also cause squeaking due to friction with the brake discs. When replacing brake pads, not only should you select high-quality ones but also ensure they are compatible with your vehicle, and be careful not to install them backward.
2. Foreign objects between the brake pads and brake discs: During driving, complex road conditions may cause sand or other debris to enter between the brake pads and discs due to the unique disc design of brakes, leading to noise when braking. Clean any foreign objects from the brake pads and discs promptly. If the brake pads or discs show significant wear, replacement is necessary.
3. Severe wear on the brake discs: Using low-quality brake pads or having hard foreign objects between the brake pads and discs can cause severe wear on the brake discs. If the wear is excessive, braking will produce noise, and the brake discs should be replaced immediately.
4. Brake pad warning: There is no fixed mileage for replacing brake pads; they should be replaced once they become thin. Some brake pads have electronic alerts, while lower-end vehicles may use warning strips. If the brake pads wear down to the warning line, they will produce noise, indicating it's time for replacement.
5. Break-in period for new cars: New cars may experience brake noise during the break-in period as the brake pads and discs need time to wear in. The noise should disappear after some driving.
6. Rust on brake discs or pads: Rain or water exposure can cause rust on the brake discs or pads, leading to squeaking when braking. Solution: Apply specialized lubricant or grease at the connection between the brake pads and calipers.
7. Abnormal brake caliper or insufficient brake fluid: Add brake fluid promptly and regularly inspect the brake caliper. Repair any faults immediately.

Precautions and inspection methods for brake pads:

1. Check thickness: New brake pads are typically around 1.5 cm thick and gradually thin with use. When the thickness reduces to one-third of the original (about 0.5 cm), inspect them visually. Owners should increase self-inspection frequency and prepare for replacement. Some vehicle designs may require tire removal for inspection. In such cases, if the warning light comes on, the metal base of the brake pad and the brake disc may already be grinding, visible as a shiny metal cut near the wheel rim.
2. Listen for sounds: If braking feels light and is accompanied by a metallic squeaking or screeching sound (which could also be due to initial pad break-in), replace the brake pads immediately.
3. Feel the pedal: If braking requires more effort or the pedal position is noticeably lower during emergency braking, the brake pads may have lost friction and must be replaced.