What Causes the Metal Friction Sound from Brake Pads?
2 Answers
Metal friction sounds from car brake pads can be caused by excessively hard brake pads, excessive wear of the brake pads, excessive wear of the brake disc or brake drum, rust on the brake caliper, slow return of the brake master cylinder, among other reasons. Below are the replacement standards for brake pads: Mileage: Under normal driving conditions, the front brake pads should be replaced approximately every 30,000 to 50,000 kilometers, and the rear brake pads every 60,000 to 100,000 kilometers. Once severe wear is detected, they should be replaced promptly. Wear Level: Generally, new brake pads are about 1.5 centimeters thick. If they wear down to one-third of their original thickness, meaning less than 5 millimeters, it is recommended to replace them immediately; If a metal friction sound is heard during braking, this may indicate that the brake pads have worn down to their minimum thickness, causing the limit indicators on both sides of the pads to contact and rub against the brake disc, producing abnormal noises—prompt replacement is necessary; If the brake pedal feels lighter than usual, or if braking feels laborious and ineffective, it indicates severe wear and insufficient thickness of the brake pads, requiring immediate replacement.
Hearing a metallic grinding sound from your brake pads likely indicates they've worn down to their limit. The metal wear indicator is now rubbing against the brake rotor, signaling it's time for replacement. This is common as prolonged use gradually thins the pads until metal contact occurs. Another possibility could be rust on the rotors or foreign objects lodged between, like small stones or metal fragments, causing screeching noises during braking. I've personally encountered this during daily driving, especially after humid weather when rotor surfaces rust. Sometimes it's due to inferior pad material or improper installation causing uneven friction. My advice: Never ignore this - visit a repair shop immediately. Delaying can damage rotors (costlier to replace) and compromise stopping distance/safety. Generally, brake pad thickness should be checked every 20,000 km to maintain optimal vehicle performance.
