What Causes Car Brake Disc Noise?

[MarleyMarie]

The causes of car brake disc noise are: 1. Insufficient tension in the brake return spring; 2. The brake pad material is too hard; 3. The brake pads were installed too close to the brake disc. Types of brake discs include: 1. By structure, they can be divided into: solid brake discs and ventilated discs. 2. By material, they can be divided into: carbon fiber ceramic brake discs and metal brake discs. Methods to determine if a brake disc needs replacement are: 1. Brake pads and brake discs wear relatively; after replacing brake pads 2 to 3 times, pay attention to checking the brake disc; 2. If you hear a rustling sound when braking, check if the brake disc needs replacement; 3. If grooves or small pits appear on the brake disc and the measured depth reaches about 1.5mm, you need to go to a repair shop or 4S store to check the brake disc.

[VonAlyssa]

I also experienced brake disc noise issues right after changing the brake pads. The common cause is insufficient bedding-in between the new brake pads and discs. If the new brake pads' surface is too smooth or the brake discs have scratches, they'll squeak when braking. It's especially noticeable after driving in the rain because moisture creates an oxide layer on the metal surfaces. Another possibility is small stones getting stuck - last time after mountain driving, I found small pebbles lodged in the tire grooves causing grinding noises during braking. I'd suggest first checking if the brake pads are too worn - regular pads need replacement every 30,000-40,000 km, and if wear exceeds 3mm, consider changing them. If the problem persists, have a mechanic inspect for disc warping. Many auto shops now offer disc resurfacing services that can solve this for just a few dozen yuan.

[DeMila]

My old car has reached 100,000 kilometers, and I know all about brake noises. There are mainly three situations: squealing when lightly braking at low speeds is usually due to the material of the brake pads, as some cheap ones contain too many metal particles; a thumping sound during heavy braking often indicates warped brake discs, especially if you park immediately after washing the car, which can cause uneven heating of the discs; the third scenario is metallic grinding noises after rain, which is normal due to surface rust on the brake discs. I once opted for cheaper aftermarket brake pads, and they started making noise after just 2,000 kilometers. A reminder to everyone: when replacing brake pads, remember to resurface the discs as well, otherwise the new pads won’t match the old discs properly. Nowadays, high-end ceramic brake pads rarely have this issue, though they’re not exactly wallet-friendly.

[ValeriaLee]

Brake disc noise is not only annoying but also unsettling. The most common cause is sand or small stones getting stuck between the brake pads and discs, creating a screeching sound similar to nails on a chalkboard. This happens especially often after driving on rural dirt roads. Another possible reason is lack of lubrication in the positioning pins, which can produce a buzzing vibration noise. Last time I went for maintenance, I had them completely disassemble and clean the brake caliper assembly, flush out all the sand and mud, and apply noise-reducing paste to all moving parts—it only cost around a hundred bucks. I recommend not braking immediately after going through puddles to prevent the brake pads from hardening. If the noise only occurs for a few moments when starting the car cold, it’s usually not a problem and will go away after a few minutes of driving.

[DelWalker]

It's quite common to hear abnormal noises after installing new brake pads, mainly due to improper installation. I encountered this when helping my neighbor install brake pads—the retaining spring wasn't secured tightly, causing a clicking sound. Sometimes, missing one anti-vibration shim can also lead to rattling noises. If it's a metallic scraping sound, it's likely because the anti-squeal shim wasn't coated with the specialized adhesive that comes with the brake pad kit. I recommend driving gently for the first 200 kilometers after installing new brake pads to allow the brake material to bed in properly. Nowadays, some brake discs come with grooves specifically designed to reduce noise—those small grooves help scrape off the hardened layer on the brake pad surface. Also, remember to regularly check the brake fluid's water content; exceeding 3% can affect braking performance.

[DiCali]

I've been researching brake noise for years, and it ultimately boils down to two causes: vibration friction and resonance. Brake pads that are too hard or too soft can cause squealing vibrations, especially louder after rain because water changes the friction coefficient. Brake discs with grooves deeper than 1.5mm should be replaced directly, otherwise they'll scrape like a record player needle creating noise. Sticky caliper guide pins cause uneven friction, producing intermittent clicking sounds. Many people don't realize winter cold can harden rubber dust boots and create noise. The solution is actually simple: switch to softer material brake pads, regularly clean brake dust, check caliper retraction, and finally lubricate all moving parts.