Brake Pad Wear Sensors: 3 Types

Brake pad wear sensors have been in use for a long time. They started with a simple tab or plate inside the brake pad and have evolved through several design stages. They are a common feature in most modern vehicles. Brake pad wear sensors notify drivers when it’s time to replace worn brake pads. They are especially helpful when the brake pad replacement falls outside the recommended brake maintenance interval.

3 Types of Brake Pad Wear Sensors

All three types of brake pad wear sensors are ‘early warning signs’ of brake pad wear. Although their design differs, they all inform motorists that their brakes need immediate maintenance. 

Acoustic (Squealer) Indicator

The acoustic wear indicator is a mechanical component that does not trigger a dashboard warning light. It is often found on older model vehicles. The indicator can be a scratch plate attached to the brake pad’s base plate or a metal tab attached to the brake pad itself. 

When your brake pad wears down past the minimum thickness, the brake disc touches this metal component during braking. This contact against the rotating rotor creates a loud and unpleasant squealing sound, which indicates the need for a brake pad replacement.

Electronic Brake Wear Sensor (One or Two-Stage)

• The one-stage electronic brake wear sensor consists of a wear indicator within the brake pad, an electrical circuit, and a dashboard warning light. When the brake pad wears down to a specific thickness, it engages an electronic contact fused into it, completing the circuit and triggering the brake maintenance dash indicator to turn on. 
• The newest two-stage electronic brake wear sensor includes two electrical circuits in the brake pad housing at different heights. The first circuit is exposed due to brake pad wear but has not yet triggered the dash warning light. The brake system then collects data on braking activity. This data estimates how much brake pad life is left before the second circuit is exposed, activating the dashboard warning light. 

Magnetic Brake Wear Sensor

The magnetic brake wear sensor uses a magnetic field to gauge the distance between the sensor and the brake rotor. The diminishing distance alters the magnetic field as the brake pad wears, activating the sensor to send a warning signal.

Brake Maintenance Intervals

Your vehicle’s owner’s manual recommends specific time and mile markers for brake pad replacement and maintenance intervals. However, many things can impact the lifespan of your brake pads and brake pad wear sensors. Road conditions, driving style, and environmental factors can significantly shorten service interval times. A qualified auto technician can examine the brake pads, verify their condition, and advise if it’s time for brake pad replacement.

Schedule Brake Pad Replacement Service

Brake pad wear sensors are valuable safety features providing warnings about worn brake pads. Combining information from wear sensors with regular visual inspections and professional evaluations at All A’s Automotive will ensure safe braking performance. 

Call us at (989)631-4672 or visit our website to schedule your brake service.