For many drivers, squealing brakes are the first indication that their pads are worn out and in need of replacement. This annoying sound is created by a wear indicator embedded into the brake pads. As the friction material on the pads wears away, it exposes the metal wear indicator. Once exposed, the indicator rubs against your metal brake discs, creating the squealing sound commonly associated with failing brakes. While these simple metal tabs are still present in modern pads, newer vehicles have added a dose of technology to the mix, providing a warning light on your dash as your pads wear down.

How Do Brake Warning Lights Work?

The simplest form of brake sensor isn't much more complicated than a basic wear indicator. These sensors are sacrificial devices that are installed through the pad. Once enough friction material wears away, the sensor is destroyed by making contact with the metal rotor. When the sensor is destroyed, it breaks an electrical circuit and triggers a warning light on your dash. More advanced sensors provide progressive information on the state of your brake pads. These sensors have multiple integrated resistors which are worn away in series, changing the resistance of the sensor and allowing your car's computer to provide an estimate of your remaining brake life.

What Sensors Are Measuring

Despite their simplicity, brake pad sensors provide you with important information about the state of your vehicle's brakes. A basic sacrificial sensor is usually designed to fail when pad thickness falls to around 6mm. Below this thickness, your brake pads will continue to function, but replacement is necessary soon. Progressive sensors provide you with more information but are likewise designed to fail entirely once your pads fall below minimum thickness. In most cases, the minimum thickness for a progressive sensor will be roughly the same as a basic wear sensor.

Can You Ignore The Light?

The simple answer is "no." Once your vehicle's brake replacement light has been triggered, you should be preparing for a pad replacement shortly. Brake wear varies by driving conditions and driving style, but a pad with less than 6mm of thickness remaining is unlikely to last more than a month or two before become dangerously thin. Once your brake pad's friction material has been worn away, your rotors will make direct contact with the pad backing material. This loss of friction material will greatly reduce your vehicle's stopping power and potentially cause damage to other components in your braking system. Prompt pad replacement is the best option to keep your car safe and to prevent expensive future repairs.

For more information, contact a company like Furgerson's Garage.