The wheel hub reminds everyone that the brake system brakes should be sensitive to the long-running car, and the brake system is prone to problems. In some car repair shops, the car line that came to check the brake system started a long line. First, it is necessary to observe whether the surface of the brake disc is smooth. If there is obvious groove, this is because when the vehicle is driving on the gravel road, some small sandstone is stuck between the brake disc and the fender, and the surface of the brake disc is continuously rubbed. As a result, if the situation will seriously affect the braking performance, then open to the designated service station to check if it is necessary to replace the brake pads. If the brake oil level is found to be lower, immediately check the brake oil circuit for leaks. Before cleaning the brakes, carefully wipe the dirt on the main cylinder to prevent dirt from falling into the storage tank. For cylinders without scale, keep the liquid level 6 mm from the top of the cylinder. If there is a scale, just keep the liquid level higher than the scale.