What Causes Deep Scratches on Brake Discs?

[Gary]

Deep scratches on brake discs are caused by friction between the brake pads and the discs. If the scratches are evenly distributed and relatively shallow, this is considered normal. Brake discs, also known as rotors, are metal discs fixed to the wheels and rotate with them, typically made of alloy steel. Below are the functions of the braking system: 1. Service Braking: During driving, the service brake (foot brake) is commonly used to slow down the vehicle or bring it to a stop within the shortest distance possible; it also helps maintain stable speed when driving downhill. 2. Parking Brake: The parking brake not only keeps the vehicle stationary but can also be used if the service brake fails. Once the vehicle is parked, the parking brake (handbrake) should be engaged to prevent the vehicle from rolling forward or backward.

[McKatherine]

As a car owner with over a decade of driving experience, I've seen many brake discs develop deep scratches. Common causes include uneven wear of brake pads or embedded hard impurities, such as sand or metal fragments, which can scratch the disc surface. Another factor is foreign objects entering the brake system, like driving on dusty roads without timely cleaning, causing sand particles to get stuck between the brake pads and create grooves during friction. Improper installation of brake pads or rust and corrosion on the disc surface can also lead to scratches when braking. These scratches not only affect appearance but, more seriously, can increase brake noise, reduce performance, and extend stopping distances in emergencies, raising the risk of accidents. I recommend checking the disc condition every time you replace the brake pads. If deep scratches are found, visit a professional shop promptly to determine if resurfacing or disc replacement is needed. Regular vehicle maintenance can prevent such issues—don't wait until a major problem occurs to regret it.

[SamanthaDella]

I remember encountering a similar issue when helping a friend repair their car. Deep scratches on brake discs are often caused by brake pads that are too hard in material or contain metal particles, which act like sandpaper grinding against the disc with each brake application, leaving marks. Additionally, driving in harsh environments can lead to sand or small stones getting lodged in the brake gaps, eventually causing deep grooves over time. Careless handling during wheel installation can also scratch the discs. When inspecting, feel the depth of the scratches—shallow ones can be smoothed out by grinding, but deep ones require disc replacement. Otherwise, you might hear screeching noises while driving, and the braking performance becomes dangerously unresponsive. Regular cleaning of the wheel hubs and brake system during maintenance can effectively prevent such scratches.

[PrestonLee]

My new car is only half a year old, and a few days ago when I was washing it, I noticed several deep scratches on the brake discs, which really startled me. I talked to the technician at the 4S dealership, and he said it might be due to poor-quality brake pads containing impurities or frequent sudden braking in the city causing uneven friction. Someone also mentioned that driving in rainy areas can cause the discs and pads to rust easily, and when braking, the rust flakes can scrape off and create grooves. This issue not only affects braking performance but could also wear out the tires faster. I don’t know much about cars, but I know safety comes first, so I need to get it repaired as soon as possible.