What is an indicator used in air disk brakes for pad wear?

An embedded indicator that contacts the rotor is an integral part of air disc brakes, designed specifically to alert technicians and drivers about the wear status of the brake pads. This type of wear indicator typically consists of a small metal tab or a similar component that is installed within the brake pad itself. As the pad material wears down during normal braking operations, the embedded indicator eventually makes contact with the rotor once a certain thickness of the pad has been worn away. This contact generates a noticeable change or sound, thereby signaling that the pads need to be replaced.

In contrast, other methods do not provide a direct or reliable indication of brake pad wear. A visual inspection method may miss subtle changes and often requires more time to accurately assess the condition of the pads. A pressure gauge is primarily used to monitor the air pressure in the braking system rather than pad condition. Likewise, a sound alert system could be beneficial in alerting the driver to certain faults or conditions within the braking system but is not directly tied to the specific wear status of the brake pads themselves. Thus, the embedded indicator serves as a precise, effective mechanism for identifying when brake pads need attention.