What Causes the Squealing Noise When Braking at Low Speeds in a BMW?
2 Answers
Low-speed braking squealing noise may be caused by foreign objects such as sand between the brake pads and brake discs. Here are the relevant details: 1. Braking System: Braking, also known as deceleration, refers to the action of stopping or reducing the speed of moving locomotives, vehicles, and other transportation tools or machinery. The general principle of braking is to fix a wheel or disc on the high-speed shaft of the machine and install corresponding brake shoes, bands, or discs on the machine base, which generate braking torque under external force. 2. Brake Pads: Automobile brake pads, also called brake linings, refer to the friction materials fixed on the brake drums or discs rotating with the wheels. The friction linings and blocks bear external pressure to generate friction, thereby decelerating the vehicle.
I've been driving a BMW 3 Series for two years, and there's always a screeching sound when braking at low speeds, which is particularly annoying. After checking some information, there are several common reasons for this situation. First, it could be an issue with the brake pad material. Many BMW models use semi-metallic brake pads, which tend to generate heat and produce a screeching sound at low speeds, sounding like metal friction. Second, the brake discs might be uneven or rusty, especially after rain or prolonged parking, causing a squeaking noise when braking. Third, when the brake pads are nearing their wear limit, the warning tabs will make a noise to remind you to replace them. Fourth, improper installation, such as insufficient lubrication at the support points, can lead to abnormal sounds. My own experience is to first get it checked at a 4S shop or a professional workshop. The technician can use a metal hook to pry and confirm the cause. Replacing the brake pads costs a few hundred dollars, but ignoring it will increase brake disc wear and cost more in the long run. I usually park in a well-ventilated garage to reduce the chance of rust.
