Is it normal for brake discs to rust after a car has been parked for a long time?
3 Answers
It is normal for brake discs to develop a ring of rust when the car is parked in a place with high humidity for an extended period. Below is some relevant information about brake pads: 1. Classification of brake pads: Asbestos brake pads (mostly phased out), semi-metallic brake pads, low-metallic brake pads, NAO formula brake pads, ceramic brake pads, NAO ceramic brake pads. 2. Ceramic brake pads vs. traditional brake pads: In traditional brake pads, metal is the main material that generates friction, providing strong braking force but with high wear and a tendency to produce noise. After installing ceramic brake pads, abnormal squealing (clicking sounds) will not occur during normal driving. Since ceramic brake pads do not contain metal components, they avoid the metal screeching noise caused by friction between traditional metal brake pads and their counterparts (i.e., brake pads and brake discs). 3. Stable friction coefficient: Ordinary brake pads have immature friction materials, and a friction coefficient that is too high can lead to unsafe factors such as loss of control during braking, pad burning, and scratching of the brake discs. Even when the brake disc temperature reaches as high as 650 degrees, the friction coefficient of ceramic brake pads remains around 0.45-0.55, ensuring the vehicle maintains good braking performance.
From my years of experience in automotive repair, brake disc rust is very common when vehicles are parked for extended periods. When a car sits idle for too long, especially in humid environments, the exposed iron material of the brake discs tends to oxidize and form rust layers. However, this isn't a major issue – just drive the car and apply the brakes a few times to wear off the rust, and normal braking performance will be restored. But if the rust is too thick and causes uneven disc surfaces, it may lead to brake shudder or unusual noises. I recommend driving the car periodically, at least taking short trips once a week to prevent moisture buildup. When parking, choose dry and sheltered spots, and using a car cover also helps. Other similar parking-related issues like battery discharge or insufficient tire pressure also require simple maintenance to ensure safe driving. Overall, rust is a minor problem, but don't overlook the safety hazards caused by severe rusting – have it checked at a professional shop when necessary.
I remember last year when I didn't drive my car for three months during a business trip. Upon returning, the brake discs were covered in brownish rust, which was quite alarming. I immediately took the car for a few short drives around the neighborhood, stepped on the brakes a few times, and the rust gradually disappeared. That experience taught me to pay attention to ventilation when parking for long periods. If the parking spot is humid, buying a waterproof car cover can be quite effective. Now before going on trips, I either ask a friend to take the car for short drives or make time to drive it myself on weekends. If the rust isn't severe, driving can wear it off, but if the rust is too deep, you need to be cautious about brake failure or damage to the disc surface. Parking-related issues like dead batteries or tire deformation are even more troublesome than rust. Developing a habit of regular car use can prevent these problems, which is beneficial for overall car maintenance and gives peace of mind.
