Why does the automatic transmission make noise when slowly releasing the brake?

[MacAthena]

Automatic transmission making noise when slowly releasing the brake may be due to the friction between the brake pads and the brake disc, which is normal. The car's braking system consists of a vacuum booster pump, master brake cylinder, brake caliper, brake pads, and brake disc. After opening the engine hood, you can see a metal disc below the windshield on the driver's side, which is the vacuum booster pump. The brake caliper is what we commonly refer to as the brake caliper. In front of the vacuum booster pump is the master brake cylinder, which has an oil reservoir on top for holding brake fluid. Brake fluid is a liquid that easily absorbs water. If the brake fluid has too much water content, it can lead to reduced braking force.

[JosieLee]

As a veteran driver with over 20 years of experience, I find the squeaking sound when slowly releasing the brakes to be quite common. It's usually caused by slight rust or dust on the brake discs, especially when starting the car in the morning or after rainy days - the cold iron discs oxidize when wet and make friction noises. I've seen many cars with this issue; if the sound is minor and only occurs when gently releasing the brakes, it's generally not a problem. However, if the noise becomes a grinding sound or occurs more frequently, it might indicate worn brake pads needing replacement. For regular maintenance, park in shaded areas to reduce rust, and rinse the wheel hubs when washing the car. Remember to regularly check brake pad thickness - replace them when they wear below 2-3mm to avoid major issues.

[JesseRose]

I’ve been driving an automatic transmission car for just over half a year, and the first time I heard the slow brake release sound, I was quite nervous. Later, I asked a friend and learned that this is a normal phenomenon caused by rust on the brake discs, especially in humid weather or after the car has been parked for a long time without moving. As long as the sound isn’t sharp or harsh, driving a few kilometers to let the friction work can reduce it. However, if the sound is continuous like metal grinding, it indicates a problem with the brake system, such as loose calipers or warped discs. I went to the 4S shop for a simple check, and the mechanic said new cars might also experience this during the break-in period. My advice is not to panic—try pressing the brakes a few more times while driving to observe any changes in the sound. If it persists, go to a professional shop for a thorough inspection.

[EmiliaDella]

For those with some knowledge about cars, slow-release brake squealing is often caused by friction between brake components. Rusty rotors can scrape and produce noise when pressure is released, especially noticeable on rainy days. If the sound is brief and mild, a simple cleaning will suffice; if the noise becomes louder, it may indicate excessive brake pad wear or a stuck caliper due to aging. A simple diagnostic method: gently press the brake a few times while parked—if the noise disappears, it's likely a dust issue. Long-term neglect can accelerate component damage, so it's recommended to inspect the brake pads yourself every 5,000 kilometers or have a technician check them. This approach saves money while ensuring driving safety.

[Crystal]

Family cars emphasize cost-effectiveness, so don't panic if you hear a slight noise when slowly releasing the brakes. Most of the time, it's caused by minor corrosion or dust on the brake disc surface, which can be resolved by simply rinsing the wheels when washing your car. However, ignoring it may lead to louder noises and potentially expensive replacement of the entire brake disc and pad set. I've tried DIY inspection: removing the wheel to check the brake pad thickness—if it's as thin as a piece of paper, it's time to visit the repair shop. Regular habits like avoiding sudden braking and parking in muddy or waterlogged areas can prevent issues. The cost is minimal—a hundred-yuan maintenance can save you thousands in potential repairs.