What are the causes of brake pad noise?

[VanMakayla]

The causes of brake pad noise are: 1. Insufficient contact surface, leading to increased pressure per unit area of the brake pad; 2. Emergency braking causing changes in the performance of the friction material; 3. Rust on the brake caliper; 4. Slow return of the brake master cylinder. The solutions for brake pad noise are: 1. Replace the brake pads; 2. Secure the brake caliper and spring; 3. Replace the brake disc. The steps for replacing brake pads are: 1. Remove the wheel of the brake; 2. Use a wrench to remove the brake caliper bolts and take out the brake pads; 3. Clean the debris from the brake caliper with a cloth; 4. Install the new brake pads onto the brake caliper; 5. Tighten the guide bolts and check the braking effect.

[JackLee]

I've also encountered squeaky brake pads while driving before. It's usually caused by small stones getting stuck between the brake disc and pad, creating that metallic scraping sound when braking. Another common situation is when the brake pads are worn down to the warning indicator, and that metal piece makes a particularly sharp noise when contacting the disc. Newly replaced brake pads might also squeak for a few days as the surfaces break in. Rust on brake discs after rain can cause a brief squeal too. If the noise persists continuously, you should consider possible issues like warped brake discs or improper installation. The most dangerous scenario is completely worn-through brake pads - not only is it hazardous but can also damage the brake discs. Any persistent abnormal noise should be checked immediately.

[DeBradley]

My neighbor just ran into this issue—her car makes a squeaking noise whenever she brakes. I went to take a look and found that the most common causes are usually one of three things: foreign objects stuck in the brake system, like small stones kicked up from the road; the metal wear indicator scraping when the brake pads are worn to their limit; or new brake pads that haven't yet been properly broken in and smoothed out. Actually, after rain, surface rust on the brake discs can also cause brief abnormal noises. If the noise persists after driving a few hundred kilometers, it's likely due to warped brake discs. This needs to be fixed immediately—otherwise, at best, it'll damage the discs, and at worst, it could affect braking distance.

[LeSawyer]

Brake noise can be mainly categorized into three types: material issues (brake pads with high metal content are prone to noise), wear condition (the warning sound from severely worn pads is the most piercing), and external factors (such as trapped stones or rust after rain). Additionally, new cars or newly replaced brake pads may produce noise during the break-in period, which is normal. Recommended inspection sequence: first, listen to the sound characteristics (metallic scraping sounds often indicate foreign objects), then observe the driving conditions (whether the noise occurs during cold starts or persists), and finally, check the brake disc surface for obvious grooves.

[Martin]

Last time when helping a friend fix his car, I noticed abnormal brake noises, which are most commonly caused by brake pad issues. It could be due to sand or stones stuck in the pads, or excessive wear triggering the metal wear indicator. On rainy days, surface rust on the brake discs can also cause brief squeaking. However, the most troublesome issue is warped brake discs—this produces a sharp noise accompanied by vibrations. Additionally, newly replaced brake pads may produce break-in noises for 1-2 weeks. The key is to observe the frequency of the noise: continuous noise indicates potential brake pad wear, while occasional noise might be due to debris. For safety, it's recommended to check the brake pad thickness every 5,000 kilometers or so—don't wait until they're completely worn down to address the issue.