Capteurs d'usure de frein
Brake wear sensors warn the driver when the brake friction material has worn down to its replacement point. Because pad and lining life varies widely with load, terrain, and driving style, the sensor removes the guesswork by signalling when service is due. They are common on modern vehicles, including many commercial ones.
An electronic sensor is a small wire loop carrying a low current. As the pad wears, the loop is exposed and contacts the disc, changing the circuit and lighting a warning on the dashboard. Two-stage sensors use two circuits to also estimate the remaining pad life. A simpler acoustic indicator is a metal tab that scrapes the disc and makes a squealing sound instead.
The sensor reports pad wear rather than wearing out on its own, but an electronic sensor is usually damaged once it has triggered, so it is commonly replaced together with the pads. When the brake warning light comes on, the brakes should be inspected without delay. Reusing a triggered or damaged sensor is not recommended.
The correct sensor depends on the vehicle model, brake system, and sensor type and position, for example one-stage or two-stage. Confirm the part against the vehicle specification before fitting.
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Frequently asked questions
What does a brake wear sensor do?
It signals when the brake friction material has worn to its replacement point, either by lighting a dashboard warning or, in acoustic types, by making a squealing sound.
What should I do when the brake warning light comes on?
Have the brakes inspected without delay. The light usually means the pads have reached their wear point and need a qualified technician to check and replace them.
Should the sensor be replaced when the pads are replaced?
Usually yes. An electronic sensor is often damaged once it has contacted the disc, so it is commonly replaced together with the pads.
What is the difference between acoustic and electronic wear indicators?
An acoustic indicator is a metal tab that makes a squealing noise against the disc. An electronic sensor completes or breaks a circuit to light a dashboard warning, and some types estimate the remaining pad life.
Can pad wear be checked without a sensor?
Yes, through regular inspection of the friction material thickness by a technician. The sensor is a helpful aid, not a replacement for periodic checks.