Even though ADAS, regenerative braking and other new technologies are getting more attention these days, the number-one brake-related complaint that brings customers back into the shop continues to be the annoying problem of brake noise.

There are a number of issues that can lead to that annoying screech, ranging from simple and easily resolved to complicated and expensive. Here’s a rundown of the most common factors that can cause noise, and how to explain them to your customer.

Friction Material: One of the primary causes of brake noise is the friction material used in the brake pads. Certain types of brake pads, such as semi-metallic or metallic pads, tend to produce more noise during braking compared to organic or ceramic pads.

Vibration: Brake noise can also result from the vibration of various brake system components. When the brakes are applied, vibrations can occur due to uneven rotor surfaces, worn-out brake pads, or loose calipers. These vibrations generate audible sounds.

Brake Pad Glazing: Over time, brake pads can develop a smooth and glossy surface due to excessive heat or incorrect bedding-in procedures. This glazing can reduce the pad’s ability to grip the rotor properly, leading to noise during braking.

Rotor Quality: Poor rotor quality or improper installation can contribute to brake noise. Rotors with uneven surfaces, excessive wear, or improper machining can cause vibrations and noise when the brakes are applied.

Moisture or Contaminants: Moisture, dirt, or other contaminants on the brake rotor or pad surface can create noise. These substances can cause uneven friction and interfere with the smooth operation of the braking system.

Wear Indicators: Some brake pads have wear indicators that produce a high-pitched squealing sound when the pads are close to their minimum thickness. This noise serves as a warning to replace the pads before further damage occurs.

Caliper Issues: Malfunctioning or improperly lubricated brake calipers can result in uneven pressure distribution on the brake pads. This uneven contact can cause noise and uneven wear of the pads.

Environmental Factors: Extreme temperatures, such as excessive heat or cold, can affect the performance of the braking system and contribute to noise. Additionally, road conditions, such as dusty or gravelly surfaces, can introduce debris that affects brake operation and generates noise.

Poor Maintenance: Neglecting routine brake maintenance, such as not cleaning or lubricating brake components, can lead to increased noise. Regular inspections and servicing help prevent issues that can result in brake noise.

Aging and Wear: As brake components age and wear, they become more prone to generating noise. Brake pads, rotors, calipers, and other parts gradually deteriorate over time, leading to increased noise during braking.