Brake pads wear out smoothly and progressively, which is why many drivers get used to the changes in the behavior of their car and miss the moment for timely intervention. The first clear acoustic signal of an exhausted resource is the appearance of unusual sounds when applying pressure to the brake pedal. Metallic scraping, high-frequency squealing or unusual creaking usually mean that the friction layer has been completely erased and the part is now in direct contact with the cast iron disc.
The second critical sign is related to the change in the hydraulic feel and reaction of the system itself. With a loss of density in the friction surface, the pedal loses its informativeness, softens or sinks excessively deep compared to its usual position. The opposite scenario – too sharp and uncontrollable biting at the slightest touch - is also a clear signal of an anomaly. An extended braking distance with the same physical effort signals both thermal overheating of the material and possible problems with the hydraulic fluid.
The third way to diagnose is a quick visual inspection, which does not require a visit to a service station for vehicles with alloy wheels. The residual threshold of the friction layer itself is easily visible through the spokes. The safe zone requires a minimum of three to four millimeters of thickness, while going below the two-millimeter limit carries a direct risk of breaking the brake disc and costly damage to the entire device.