Why is there a metal friction sound when the car is driving at low speed?

[ElijahAnn]

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.

[LeCamilla]

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.

[McKira]

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.

[McNevaeh]

Buddy, that sound you mentioned is all too familiar to me! Just dealt with it last month. Focus on three key points: First, check the brake pad thickness – the sound of the metal wear indicator scraping against the rotor is like nails on a chalkboard. Second, feel the wheel hub temperature; if one side is abnormally hot, it might indicate a stuck caliper causing constant brake pad friction. Third, inspect the undercarriage – cracked stabilizer bar bushings will make a creaking noise over speed bumps. In my case, it was a loose lower control arm ball joint that made creaking sounds like a rusty door hinge during low-speed turns. Truth is, a repair shop can pinpoint the issue in just ten minutes with the car on the lift.

[GrahamFitz]

Low-speed metallic noises often originate from chassis resonance. With the vehicle lifted, first inspect whether the exhaust system hangers are broken, as loose exhaust pipes can strike the subframe; then measure the brake disc thickness, as excessively thin discs will continuously rub after thermal deformation. Next, check if the steering tie rod dust covers are torn, as dry steering knuckles lacking lubrication will produce rough friction sounds. Also, pay attention to driveshaft universal joint wear. Such noises typically disappear as speed increases because high-frequency vibrations mask the friction sounds. It is recommended to use a stethoscope to precisely locate the sound source before performing repairs.