What Causes the Squeaking of Newly Replaced Brake Pads?
3 Answers
Newly replaced brake pads may squeak due to misaligned installation, foreign objects on the pads, inconsistent friction blocks, or mismatched contact surfaces. Misaligned Installation: The mechanic may have installed the brake pads incorrectly. Upon removal, you can observe that only part of the pad surface shows friction marks. Foreign Objects on the Pads: Sudden noise after driving for a while is often caused by hard objects like gravel or metal scraps getting stuck between the brake pads when braking. Inconsistent Friction Blocks: Due to manufacturer issues, friction blocks of the same brake pad model may vary in size, especially in width. Some manufacturers have size deviations of up to 3mm, making the brake disc surface appear smooth. However, larger pads installed on discs previously used with smaller pads will still cause noise. Mismatched Contact Surfaces: If the old brake disc isn’t resurfaced before installing new pads, the contact surfaces won’t match properly. Solutions for Squeaking New Brake Pads: Misaligned pads should be removed and reinstalled at a 4S shop. Pads with foreign objects need cleaning at a 4S shop. For inconsistent friction blocks, resurfacing the disc is recommended. Alternatively, driving for a while until the surfaces match can eliminate noise. For mismatched contact surfaces, remove the pads and resurface the disc.
I've encountered a similar situation recently. It's quite common for new brake pads to squeak when first used, mostly because they haven't been properly broken in. I remember when I first changed to a new set of pads, every time I braked for the first few days, it sounded like scraping a plate, but after driving a few dozen kilometers, it was fine. However, if the noise persists for too long, you should consider whether it's an installation issue, such as loose screws or the brake pads being installed backwards. In such cases, you should quickly return to the repair shop for adjustment. It could also be that the brake disc is uneven, causing the new pads and old disc not to fit together properly, especially in older cars. Also, don't skimp on cheap, inferior brake pads—too many metal particles or mismatched hardness can cause abnormal noises. For safety's sake, if the noise persists for more than a week, it's best to get a comprehensive check-up. After all, you can't be careless with the braking system.
I often encounter this issue in the workshop. When new brake pads produce abnormal noises, the first thing to check is whether the installation was done properly. Some mechanics cut corners by not cleaning the iron filings off the brake calipers before installing new pads, which leads to foreign objects getting stuck between the friction surfaces. Additionally, uneven application of the anti-noise paste on the back of the brake pads can cause resonance and noise. A proper installation requires a thin, even layer of paste. From many cases I've observed, if the edges of the brake discs have step-like wear, the new pads will make a sharp noise when they come into contact with these edges. In such cases, the discs need to be resurfaced. Of course, environmental factors also play a role. For example, after rain or washing the car, the brake discs may rust, causing a rustling sound during the first few brakes, which is normal. I recommend that owners avoid hard braking during the break-in period. After driving about a hundred kilometers, the noise usually disappears.
