Why is the brake disc of my newly purchased car rusting?
2 Answers
The rusting of the brake disc on a newly purchased car mainly depends on the material of the brake disc. Currently, most household cars use brake discs made of gray cast iron 250 standard, which offers excellent braking performance but has a high carbon content and lacks surface rust protection, making rust inevitable. More details about brake discs are as follows: Function of brake discs: A brake disc is a circular disc that rotates as the car moves. The braking force is generated when the brake caliper clamps the brake disc, slowing down or stopping the vehicle when the brakes are applied. Brake discs provide effective braking performance and are easier to maintain compared to drum brakes. Types of brake discs: Braking systems include disc brakes, drum brakes, and air brakes. Older cars often feature front disc brakes and rear drum brakes, while many modern cars have disc brakes on both front and rear wheels. Disc brakes dissipate heat better than drum brakes, reducing the likelihood of heat fade during high-speed braking, thus offering superior high-speed braking performance. However, their braking efficiency is inferior to drum brakes during low-speed cold braking.
When I bought my new car, the brake discs were also rusty, which startled me at first, making me think there was something wrong with the car. Later, I asked an experienced driver and learned that brake discs are made of iron or steel. New cars, when stored or transported in humid environments, can develop rust in just a day or two. This doesn’t indicate poor quality; it’s a normal physical phenomenon. After driving for a few days, the brake pads will wear off the rust, and the disc surface will become clean. If the rust is too thick and causes brake noise or vibration, just go to the shop for a simple polish. Don’t worry too much; drive more and maintain your car regularly, and it will be fine.
