What Causes Rust and Clicking Sounds on Brake Pads?
2 Answers
Rust and clicking sounds on brake pads are caused by slight rust on the brake discs. If there is only minor surface rust, it can be removed by continuous braking while driving, and no special treatment is needed, as the slight rust on the brake discs will be worn away by braking during normal vehicle operation. Below is relevant information about brake pads: Types of brake pads: Asbestos brake pads (mostly obsolete), semi-metallic brake pads, low-metallic brake pads, NAO formula brake pads, ceramic brake pads, and NAO ceramic brake pads. Ceramic vs. traditional brake pads: In traditional brake pads, metal is the primary material generating friction, providing strong braking force but with higher wear and noise. After installing ceramic brake pads, abnormal noises (such as squealing) do not occur during normal driving. Since ceramic brake pads contain no metal components, they avoid the metal-on-metal friction noise between traditional metal brake pads and their counterparts (i.e., brake pads and discs).
I just experienced this situation. After parking the car in the rain, the brake pads rusted, and there was a clunking sound when starting. A friend said it was due to oxidation of the metal parts, and the uneven friction caused by rust layers where rainwater accumulated near the wheels. Driving a few kilometers while lightly applying the brakes can remove most of the rust, and the sound will disappear. But if the noise persists, be cautious about excessively worn brake pads or foreign objects stuck in the caliper. I ignored it last year and almost had an accident. Since then, I've been regularly maintaining and checking the brake thickness to ensure it's within the safe limit. For prevention, park in a garage or dry place, avoiding areas with standing water. After rain or snow, dry the bottom of the wheels. Safety first—don't dismiss small noises as trivial. If necessary, have a professional shop take a look.
