What Causes Rust on Car Brakes?

[LaBrynlee]

Rust primarily depends on the material of the brake disc. If rust appears on the car's brake disc, it may be due to exposure to water or a humid environment. Since car brake discs are made of cast iron, they can develop surface rust after the car is parked for a while under conditions such as car washing, driving in rainy weather, wading through water, driving on snowy roads, frost, or in high-humidity environments. This is a normal phenomenon of oxidation and rusting when cast iron components come into contact with water. Brake discs require sufficient friction to function effectively, so they are not treated with any anti-rust coatings. If the brake disc only has slight surface rust, it can be removed by continuously applying the brakes while driving. The friction between the brake caliper and brake pads can eliminate the surface rust, restoring the brake disc to its original condition. However, ensure safety by performing this operation in a safe area. If the brake disc is severely rusted, it needs to be polished at a 4S shop or auto repair shop to remove the rust. Rust on the brake pads does not affect braking performance. The rust can easily be worn off by lightly applying the brakes while driving. Initially, there might be a squeaking sound, but it will disappear after driving a few kilometers and applying the brakes a few times. Even if the car is left unused for an extended period, there is no need to worry about the brake pads rusting excessively. If the parking location is dry, rust is even less likely to form. Braking primarily relies on the brake disc, caliper, and brake pads, with the brake pads being the most worn component. As long as the brake pads are not worn beyond their limit and the brake fluid is not deteriorated, driving safety is generally not affected. The car brake system, also known as the car braking system, functions to: decelerate or stop a moving car as required by the driver; keep a parked car stable under various road conditions (including on slopes); and maintain a stable speed for a car driving downhill. If the car remains parked for a long time without use, it is recommended to drive it every two months and apply the brakes. This helps maintain the brake discs and prevents severe rusting that could affect braking performance.