When the car is running, one foot or several feet are used to brake, the brake pedal is stepped to the end, and the brake suddenly fails. Reason: there is no brake fluid in the 1. total pump. 2. the total pump skin bowl is broken or tread. 3. point pump skin bowl damaged or tread. 4. the brake line is severely broken or joint disjointed. Diagnosis: failure of brake failure should be stopped immediately. First, observe the leakage of the brake fluid. For example, the leakage of brake fluid at the brake sleeve of the brake cylinder is serious, and it mostly belongs to the main pump skin bowl. If there is a large number of brake fluid on the edge of a wheel brake drum, it means that the cylinder of the pump is turned over or damaged seriously. Pipeline leakage brake fluid is generally visible. If there is no leakage of brake fluid, check whether the brake fluid in the main storage tank is adequate.