Brake pad wear sensor: replacement and selection

When and why it is necessary to replace brake pad wear sensor

Manufacturers do not specify exact replacement terms for this component. The electronic device should be replaced in case of wire breakage or damaging of its insulation, and in case of contacts oxidation. And the plate of the mechanical sensor can break off the brake pad during car driving.

Most often, oxidation of electronic sensor elements is the result of dirt and water got onto it. And damaging of wires and their insulation is mostly caused by poor quality of the part itself or improper installation. The plate of the mechanical device can break off due to impact.

Signs of component defect vary according to its type. Thus, if the mechanical sensor was unfastened, than, specific sound, indicating pads wear-out will be absent. Incorrect data from the corresponding dashboard indicator will point out breakdown of the electronic sensor. Thus, if the unit wires are damaged, the indicator won’t be active even if the pads are significantly worn. In this case, their lifetime end can be detected by foreign sound from the wheels side, which appears at braking. Moreover, a defective device sometimes activates even when the pads are new.

It is better to replace the sensor at a service station, as a lifting device will be necessary for this. Moreover, these works presuppose demounting of the wheel. The built-in sensors are always replaced together with the pads. But even if the device is removable, many car manufacturers recommend to install it together with a new pad. Data of the trip computer should be reseted to zero after installation of the sensor.

How to select brake pad wear sensor

These devices can be mechanical and electronic. The first type sensor is a steel plate, bended at a certain angle. It is mounted on the pad base. One of the plate sides is fastened perpendicularly to the brake disc and on the distance of minimal wear of the friction layer. When the friction pad is abraded to a certain thickness, a protruded part of the sensor starts contacting with the disk. Specific sound appears during this. These devices are used on the disc brakes only.

More advanced are the electronic brake pad wear sensors. Severe wear-out of the brake pads will be indicated the special control lamp on the dashboard if these sensors are installed in the car. The electronic brake pad wear sensors can be external or built-in. The first ones are installed in the brake pad, and special grooves for these devices are presupposed in the friction pads. The integrated sensors are pressed inside the pads.

Remember, that you safety depends on condition of the brake system. Buy high-quality sensors only. For instance, devices of Febi Bilstein, ATE, MAPCO are of that kind.

In order to properly select the component, consider length and number of connection contacts of the sensor. The axle (front or rear) and the side (left or right) where the device is installed is important as well.