Why does the car shake when the brake is pressed?

[VanVivienne]

The shaking when pressing the brake may be caused by uneven wear of the brake discs. This phenomenon mainly occurs when the driver frequently uses intermittent braking (point braking) over a long period, causing the brake discs to develop an uneven surface with alternating high and low spots. When braking, the brake pads gripping these uneven surfaces can lead to shaking. Therefore, drivers should use the brakes properly and according to standard practices to avoid such issues later. Additionally, when the car's electrical system is turned on while the engine is idling, it can cause the vehicle to shake. The engine load increases due to the electrical system being activated, leading to a drop in idle speed. To compensate for this shaking caused by the idle drop, the engine will automatically raise the RPM slightly.