What are the criteria for replacing brake discs?
3 Answers
The replacement criteria for brake discs are mainly determined by the thickness of the brake pads, the wear condition of the brake discs, and the mileage of the vehicle. Brake discs have wear limit indicators, and when these indicators disappear, the brake discs should be replaced immediately. Notes on replacing brake discs: 1. When replacing the front brake pads, all four pads on the left and right front wheels need to be replaced simultaneously, and the same applies to the rear brake pads. 2. The braking system on a car is divided into two main types: disc and drum brakes, but apart from cost advantages, drum brakes are far less efficient than disc brakes. 3. When replacing brake pads, try to use pads with the same material as the old ones. Of course, it's even better if the new brake pads are made of a higher-grade material than the original ones.
The criteria for replacing brake discs mainly focus on several aspects. Based on my 20 years of driving experience, thickness is the most critical factor. New discs are typically around 20mm, and they should be replaced once worn down to below 18mm. Deep surface scratches that affect braking performance can be measured with a caliper for depth. If the disc is warped, the car will noticeably vibrate during braking. Additionally, severe heat cracks or corrosion also require attention. Remember to inspect them every 50,000 kilometers or so—never neglect this, as the risk of brake failure increases significantly. Safety comes first. I've seen many people try to save money by delaying repairs until the problem becomes severe, only to end up spending more on fixing calipers or discs. During regular maintenance, have a technician check the thickness to ensure the braking system remains reliable, giving you peace of mind while driving.
Last time my car had abnormal brake noise, and the repair shop found the brake disc grooves were too deep and needed replacement. The mechanic said the standard is when the thickness wears below the manufacturer's specified minimum value, usually marked with a 'min' sign on each disc; if there are scratches deeper than 1mm on the surface, it should be replaced; also, thermal deformation can cause brake judder. It's recommended to check every 60,000 kilometers based on mileage. Like me, frequent hard braking may require earlier replacement. Timely replacement avoids increased braking distance and reduces accident risks. It's most convenient to check during regular maintenance—don't wait until the problem becomes severe. Maintaining the brake system is crucial for driving safety.
