Why does the GLC always make noise when braking?

[Jensen]

There are generally three reasons for the GLC's braking noise: 1. Normal ABS intervention: The sound produced when the ABS system is functioning normally. 2. Insufficient friction: Noise caused by newly replaced brake pads not being properly worn in. 3. Excessive wear: Noise resulting from excessive wear between the brake discs and brake pads. Below is an introduction to related content: ABS working principle: The Mercedes-Benz GLC is equipped with an ABS anti-lock braking system. Its working principle involves a cycle of locking and releasing, keeping the vehicle in a critical state. In this situation, sudden braking will trigger the ABS to intervene, producing abnormal noise, which is considered normal.

[VanSimon]

I have a lot to say about the brake noise issue with the GLC! My car started squeaking just six months after purchase, and I made three special trips to the 4S store. The mechanic said the main reason was that the brake pads were too hard, made with a high-metal-content formula, which tends to produce high-frequency vibration sounds when rubbing against the brake discs. It was especially noticeable on rainy days—when the rust on the brake disc surface was rubbed, it sounded like nails on a chalkboard. Another issue was that the chamfer design on the edges of the brake pads wasn’t smooth enough, making it easy for small stones to get stuck and cause strange noises. Later, I switched to ceramic-based brake pads. Although they were more expensive, they were much quieter. Now, they still make a few noises occasionally after washing the car, but it doesn’t affect safe driving at all—you just get used to it.

[LeClayton]

After 20 years of repairing cars, I've found that Mercedes-Benz brake squealing issues mostly stem from the material of the brake pads. To enhance wear resistance, OEM brake pads contain a higher proportion of metal particles in their formulation, which can cause harsh squealing noises when metal contacts metal. This is particularly noticeable during cold starts and rainy weather, as iron brake discs rust when exposed to moisture, creating friction points. Additionally, prolonged vehicle inactivity leads to oxidation on the brake disc surface, which can also generate noise when rubbed. However, these issues don't affect braking performance. If the noise is unbearable, switching to softer brake pads with a friction coefficient above 0.4 and resurfacing the brake discs can provide a more reliable solution.

[SanGeorge]

The common issue with the GLC is squeaky brakes. My colleagues always joke that my car comes with its own horn when I commute. I consulted a repair shop specifically, and they said Mercedes-Benz uses a high-metal formula for the brake pads to extend their lifespan. This hard material creates a sound like two knives scraping against each other when friction occurs. Additionally, rainy weather is frequent in the south, and water accumulation on the brake discs forms a thin film. Braking right after starting feels like scratching glass with fingernails. I’ve figured out a solution: after washing the car, don’t park immediately—drive a couple of kilometers to let the brake system dry. Every month, find a safe stretch of road and perform a medium-intensity brake at 60 km/h to wear off the surface oxides, which helps a lot.

[OJasper]

As a Mercedes owner for ten years, I've found that the key to brake noise lies in material composition. To balance braking performance and service life, manufacturers typically use brake pads with over 15% metal content - much harder than Japanese cars. When temperatures drop below 10°C or humidity exceeds 70%, metal fibers in the pads interact with rotors due to changing friction coefficients, creating that high-pitched squeal. Another hidden cause is overly tight return spring design in brake calipers, restricting pad retraction. While switching to aftermarket ceramic composite pads can eliminate noise, OEM parts actually provide shorter stopping distances despite the sound.