Why is there a metal friction sound when the car is driving at low speed?
3 Answers
When the car is driving at low speed, the metal friction sound is caused by the friction between the brake pads and the brake disc. Here are some additional details: 1. Reasons for the metal friction sound at low speed: The gap between the disc brake pads and the disc is very small, sometimes even "zero gap". When the disc is unevenly worn or has sand or stones stuck to it, a "metal friction sound" can occur at low speeds. The braking system is a crucial part of the car, as it affects both the driving stability and safety. 2. Braking system: The main components of the braking system include the vacuum booster pump, master cylinder, wheel cylinder, brake pads, and brake disc. The vacuum booster pump provides assistance, making it easier for the driver to press the brake pedal when braking.
A while ago, my car also had this kind of squeaking noise, like two pieces of metal scraping against each other. The experienced mechanic told me to focus on checking four areas: first, the brake pads—if they're worn down to the limit and the metal wear indicator is exposed, light braking at low speeds can produce a particularly sharp noise; second, the rubber bushings in the suspension—if they've aged, the chassis will make a metallic creaking sound when turning; third, if the exhaust pipe's mounting hooks are loose, the metal pipe may wobble and hit the frame, causing a clanging noise; and lastly, don’t forget the wheel hub bearings—if they run dry due to lack of lubrication, they’ll produce a humming grinding sound. If you hear these noises, don’t ignore them—get the car lifted and inspected as soon as possible.
As a female driver, I'm most afraid of strange noises while driving. Last time, I heard a 'squeaky' sound at low speed, which scared me into heading straight to the repair shop. It turned out to be due to lack of lubrication in the ball joint of the suspension system. The mechanic said it was like dry grinding without lubricant, just like a joint. They even demonstrated the wobbling amplitude of the chassis link when shaking the tire, and there were obvious wear marks at the metal connections. By the way, if the brake disc shield is deformed, it will rub against the edge of the brake disc on slightly bumpy roads, producing a particularly sharp sound. It's recommended not to delay such issues; replacing a small part can solve the problem.
