Many people check their brake pads before long drives and replace them if they are thin. This is a good habit and a necessary condition for safe driving. However, it is very dangerous to drive at high speed immediately after replacing them! Because new brake pads have poor braking performance, the braking distance will be much longer during emergency braking!
No surface of an object is perfectly flat, just like discs. Generally, sufficient braking force can only be generated and the braking effect fully utilized when the contact area between the two reaches 75%. If the contact area is too small, the friction between them during braking is relatively small, resulting in insufficient braking force and a longer braking distance. Generally, disc brake systems can achieve close to 100% contact between discs and discs, while drum brake systems are quite good with about 80% contact area.
For old brake pads and discs, due to their long-term contact and friction, the surface marks between them are consistent. For example, if there are grooves on the brake disc, there will be corresponding bulges on the brake pads; due to some reason, the brake disc partially touches the ground, and then partially touches the ground as well. They have almost 100% contact, ensuring sufficient braking force during braking.
But things are different when you replace them with new ones. The new surface is smoother, while the old brake disc surface may be uneven. After assembly, the contact area between the two may be very small, sometimes even less than 50%. Thus, during braking, due to the insufficient contact area, insufficient braking force cannot be generated, the braking distance will be longer, and there is even a risk of the car coming to a complete stop.
Do not drive at high speeds after replacing your car's brake pads.
Some people say, "My brake pads and discs are new. There shouldn't be a problem." This doesn't mean that even new pads and discs won't make 100% contact due to manufacturing errors. In addition, new pads have an oxide film on the surface, which will reduce the coefficient of friction and braking force. Therefore, after a new car leaves the factory, the brake system will undergo a break-in process according to the owner's manual. Generally, after driving 500 kilometers, the brake discs and discs will reach an ideal break-in and engagement state. Please drive carefully within this mileage.
What should we do after replacing the brake pads?
1. Drive carefully for the first 500 kilometers, and maintain a sufficient distance from the vehicle in front when braking. 1. While driving, consciously and lightly apply the brakes frequently to ensure constant contact and friction between the brake discs, allowing their surface marks to match quickly and maximizing the contact area.
2. Find an open area and increase the vehicle speed to over 100 km/h. Then, apply moderate pressure to the brakes to slow the car down until it comes to a stop. Repeat this process until the braking distance meets the requirements. During this process, be careful not to overheat the braking system. If it overheats, stop and rest. After the braking system has completely cooled down, continue the break-in process. This method is suitable for long-distance vehicles and can achieve a rapid break-in effect.
