What Causes the Squealing Noise When Brake Pads Grind Against Brake Discs?
4 Answers
Brake pads grinding against brake discs and producing squealing noises are mainly caused by the following reasons: 1. It may be due to steering wheel vibration when braking at high speeds. 2. It could be caused by poor wear on the contact surface between the brake pads and brake discs. 3. The material of the brake pads may be of poor quality, leading to noise during braking. Here are some methods to resolve the noise issue: 1. If there is no vibration after turning on the power, check whether the fuse of the electrical controller is blown, whether electrical components are loose, or whether plugs and sockets have poor contact. If the conveying speed does not meet the requirements, pay attention to the following three points: (1) Check whether the screws fastening the elastic components are loose. (2) Check whether the spring plate is broken. (3) Check whether the electromagnetic gap is too large. The normal gap for small vibrating plates should be between 0.5MM and 1.2MM for the distance between the electromagnet and the armature. The non-parallelism of the working surfaces of the iron core and armature should not exceed 0.02MM. 2. There are two reasons for the electromagnet coil overheating or burning out: (1) If the gap between the electromagnet and the armature is too large, the coil is prone to burn out. (2) Using an electromagnet designed for full-wave vibration with a half-wave power supply may result in overheating.
I've also experienced brake noise issues while driving, and found there are usually several reasons. When brake pads are nearly worn out, the metal wear indicators scraping against the rotors produce sharp squealing sounds - this is your warning to replace them. Sometimes uneven rotor surfaces, especially when rusted after rain, cause clunking noises during initial braking. It could also be the brake pad material - hard compound pads or those with embedded gravel create particularly harsh grinding sounds. My advice is to first check pad thickness and replace immediately if they're nearly gone. Always use OEM-quality replacements, or the noise will persist even after installation.
I often encounter brake noise issues when repairing cars. In most cases, it's caused by stuck guide pins, preventing the brake pads from smoothly retracting, resulting in a squealing sound as they drag against the rotor. Another common issue is hardened edges on the brake pads, especially on vehicles frequently driven in city traffic with constant braking. The edges develop a hardened lip that sounds like metal scraping against a plate. Last time, I came across a car with a warped brake rotor - the whole vehicle would shake with a metallic grinding noise when braking. The solution is actually quite simple: during maintenance, have the mechanic check the lubrication of the guide pins and resurface the edges of the brake pads. If the rotor warpage exceeds 0.05mm, it's safer to replace it with a new one.
As a female car owner, let me talk about brake noise. I experienced it last month—squeaking when lightly pressed, but silent when pressed hard. A friend checked it and said the brake pad shim had shifted. It doesn’t cost much but is crucial. Also, after washing the car and leaving it parked for a few days, the brake discs rusted, and the loud clunk when starting is normal. Now that it’s hot, this issue is more common since high brake temperatures can cause hardening. Last time I had my brake pads replaced at the dealership, the mechanic specifically showed me whether the retaining clip was properly installed, saying misalignment could also cause noise. If you’re not car-savvy, it’s safer to have a professional check it out.
