
If the brake pads are only 3mm thick, it is best to replace them immediately. Here are methods to determine whether the brake discs need to be replaced: 1. Listen for sounds: If there are abnormal noises when lightly applying the brakes, the brake pads must be replaced immediately. This is because the wear indicators on both sides of the brake pads are already directly rubbing against the brake discs, indicating that the brake pads have exceeded their limit. 2. Warning light: Typically, the decision to replace the brake discs is based on whether the brake disc warning light on the dashboard is illuminated. Normally, this light is off. When the brake discs are faulty or excessively worn, the light turns on and goes off after repairs. 3. Check the thickness: Most brake disc products have wear indicators, with three small dimples distributed on the disc surface. Use a vernier caliper to measure the depth of these dimples, which is 1.5mm. When the total wear depth on both sides of the brake disc reaches 3mm, it is recommended to replace the brake discs promptly.

From my experience as an auto mechanic, brake pads with only 3mm remaining should indeed be replaced. New pads typically measure around 10mm thick, and when worn down to 3mm, they have very limited service life left. If you frequently drive in urban areas with constant braking, they'll probably last only another 3,000-5,000 kilometers before being completely worn out. I once saw an owner who stubbornly refused to replace them, which resulted in deep grooves being worn into the brake discs, doubling the repair cost. Brake pads usually have a small metal wear indicator that produces a screeching sound when the pads are critically thin, but don't wait until you hear that warning. I recommend taking your car to a repair shop this weekend for inspection, and while you're at it, have them check the brake fluid condition too - both are crucial for driving safety.

Last time during maintenance, I was reminded that the brake pads were down to 3mm, and I hesitated and did some research. Actually, European and American car manufacturers recommend replacement when below 3mm, while Japanese cars suggest changing them when below 2mm. However, considering our complex road conditions here, with more electric vehicles and frequent sudden braking situations, waiting until the limit is too risky. My own practice is to regularly check the brake pad thickness by turning the steering wheel to full lock and using a phone flashlight for better visibility. Remember to check both front and rear wheels separately, as wear can be uneven. Nowadays, replacing with a set of ceramic brake pads only costs a few hundred bucks, which is much more cost-effective compared to the losses from a rear-end collision.

It is recommended to replace 3mm brake pads early. The braking system relies on friction materials to generate stopping power, and excessively thin pads have poor heat dissipation, making them prone to overheating and failure during continuous downhill driving. Statistics show that wear accelerates by 50% per 1,000 kilometers when thickness falls below 3mm. Also note that some vehicles with electronic wear indicators may exhibit longer braking distances even before the dashboard warning light activates—especially critical during rainy conditions when tire grip diminishes. A veteran bus driver with 30 years of experience mentioned that their transport company mandates replacement when pads wear below 4mm, emphasizing that safety thresholds must never be compromised.

As a car owner with ten years of driving experience, my advice is to prepare to replace brake pads when they wear down to 3mm. New brake pads have a friction material thickness of 10-12mm, and at 3mm, it's less than the thickness of a coin. Here's my rule of thumb: if you frequently drive on highways, replace them now; if you mainly drive in the city, you can wait until 2mm. But I don't recommend going any thinner, as it could damage the brake discs during emergency stops. I remember once on a road trip to the northwest, a local mechanic taught me a trick: if you hear metal grinding when lightly applying the brakes, it means the backing plate is about to be exposed, and you should stop driving immediately to replace them.


