Why Do the Brake Pads of a New Car Rust?

[McNoah]

This is a normal phenomenon. Brake discs are cast from pig iron. If the car remains stationary for an extended period in the dealership, especially in high-humidity conditions, rust may appear. When rust occurs, driving the car out and applying the brakes several times will wear off the rust on the brake discs. Here is additional information: Rusting Principle: To enhance braking friction, most vehicles use cast iron brake discs, except for a few high-end cars that use ceramic brake discs. Since brake discs are subject to frequent friction, they are not treated with anti-rust protection. In environments with high air humidity or during rainy weather, gray cast iron brake discs are prone to rust due to the chemical reaction between their material composition and water and air.