What is the reason for poor braking after replacing brake pads?

[VanCarlos]

Poor braking after replacing brake pads is because the surface of the new brake pads is relatively flat, while the contact surface on the brake disc is very uneven, resulting in a very small contact area between them. Additionally, when braking, the deformation of the brake pads is significant, leading to poor braking performance. Automotive brake pads, also known as automotive brake linings, refer to the friction materials fixed on the rotating brake drum or brake disc of the wheel. The friction linings and friction blocks within them bear external pressure to generate friction, thereby achieving the purpose of vehicle deceleration. Automotive brake pads consist of a steel plate, an adhesive heat insulation layer, and a friction block. The steel plate is coated to prevent rust, and the coating process is monitored using an SMT4 oven temperature tracker to ensure the temperature distribution during the coating process meets quality standards.

[StAdeline]

I've encountered this situation quite often where the brakes feel spongy after replacing the brake pads. The most common reason is air remaining in the brake system that hasn't been fully bled. The brake lines are like water pipes - air bubbles inside will affect pressure transmission, making the brake pedal feel soft. Additionally, new brake pads require a break-in period. When first installed, the friction material surface may not perfectly match the brake disc, but this improves after a few hundred kilometers of driving. The installation process also can't be ignored - abnormal caliper retraction or misaligned brake pad installation can both lead to insufficient braking force. There's also the issue of brake fluid - if you don't check the fluid's aging condition when replacing pads, high moisture content in old fluid will affect braking performance. I recommend returning to the repair shop immediately for brake line bleeding and inspection - safety can't wait.

[SavannahRose]

Last time after replacing my brake pads, I encountered a similar issue. The mechanic told me there are several key points: First, the material difference between new and old brake pads, especially after switching to ceramic compound pads, requires a few days of break-in period to achieve optimal braking performance. Second, during installation, the brake caliper pistons weren't fully retracted, preventing the pads from making complete contact with the rotors. Third, component compatibility issues, such as purchasing aftermarket pads with incorrect dimensions or using overly thick pads that prevent proper caliper positioning. All these situations can significantly increase braking distance. It's recommended to have a professional shop recheck the installation quality and adjust the caliper-to-rotor clearance if necessary.

[Brian]

Insufficient braking after replacing brake pads typically involves three aspects: substandard brake pads with insufficient friction coefficient or poor heat dissipation performance; installation errors leading to air leakage in brake lines or lack of lubrication in caliper floating pins; system coordination issues such as accidental triggering of ABS sensor fault codes. The thickness change of new brake pads also requires adjustment of the electronic parking brake reset procedure. I recommend first checking the sealing of the brake lines, eliminating air, and then using a diagnostic tool to read fault codes, paying special attention to the calibration of the brake pad thickness sensor.

[Jeanette]

The braking system emphasizes overall coordination. If newly installed brake pads exhibit weak braking performance, it's likely due to incomplete bleeding of the brake lines causing air resistance—an issue often overlooked by small repair shops. Additionally, when replacing pads on older vehicles, unevenly worn brake rotors can also reduce friction. It's advisable to simultaneously inspect the rotor surface for grooves and ensure the caliper guide pins move smoothly. If installing high-performance sintered metal brake pads, remember they require preheating to operating temperature for optimal effectiveness. Finally, test the brake fluid's moisture content; if it exceeds 4%, replacement is mandatory to ensure hydraulic transmission efficiency.