Why does the car feel like it can't stop after replacing new brake discs?
3 Answers
This is a normal phenomenon that requires a break-in period. Avoid emergency braking within 500 kilometers. Here are methods to determine whether brake discs need replacement: 1. Listen for sounds: If abnormal noises accompany light braking, the brake pads must be replaced immediately. This indicates the wear indicators on both sides of the brake pads are directly contacting the brake disc, proving the pads have exceeded their limit. 2. Warning light: Typically, the brake disc warning light on the dashboard serves as the primary indicator for replacement. Normally this light remains off; it illuminates when the brake discs are faulty or excessively worn, then turns off after repair. 3. Check thickness: Most brake disc products have wear indicators - three small dimples distributed on the disc surface. Measure the dimple depth with calipers (1.5mm standard). When total wear on both sides reaches 3mm, prompt replacement is recommended.
Feeling like the new brake discs aren't stopping well is quite common, and I've seen many similar cases. On one hand, new discs require a break-in period—it's normal for braking performance to not be fully effective right after installation. You need to drive smoothly for 300-500 km to allow the discs and brake pads to mate more tightly. If you brake aggressively too soon, it may cause uneven wear. On the other hand, there might be oversights during installation, such as misaligned discs or improperly secured brake pads, leading to insufficient friction. Insufficient brake fluid or air in the lines can also weaken braking performance. For safety, don't push through it—return to the repair shop and have a technician check the installation details and perform system tests. Don't delay, as it could affect driving safety. I recently changed my discs and felt something was off too—it turned out the old pads were too worn to match the new discs. Replacing all the components fixed it. Remember, regular maintenance can prevent major issues.
Poor braking performance after installing new brake rotors can be analyzed from several aspects. New components require a break-in period – braking typically stabilizes within a few hundred kilometers, but slightly reduced initial stopping power is normal during this phase. Improper installation is a common cause, such as uneven rotor mounting or loose brake pad clips affecting contact surfaces. Component mismatch is another possibility, where differences in material or dimensions between OEM and aftermarket rotors create uneven friction. Additionally, inspect the brake system: air bubbles in lines or low fluid levels can cause weak braking. As a mechanic, I always recommend replacing pads simultaneously to avoid compatibility issues. If problems persist after the break-in period, immediately consult professionals – never overlook minor details that could lead to major safety hazards.
