Why does a new car make noise when braking?

[VeraAnn]

The reason a new car makes noise when braking is that the brake pads are new and need to be broken in. The noise will disappear after several hundred kilometers of driving. The function of brakes is to reduce speed or bring the vehicle to a stop. Their working principle relies on the friction between the brake pads and brake drums, as well as between the tires and the road surface, converting the kinetic energy of the moving vehicle into heat energy through friction, thereby slowing down or stopping the vehicle. Causes of brake failure include: 1. Impurities in the master cylinder or poor sealing; 2. Failure of the vacuum booster; 3. Contaminated brake fluid; 4. Leakage in the master cylinder or wheel cylinder; 5. Air leakage from the air reservoir or pipeline connections; 6. Severe overloading; 7. Carbonization of the brake drum; 8. Insufficient brake fluid in the master cylinder; 9. Wear of the master cylinder piston.

[McHarmony]

I just bought a new car, and there's a slight squeaking sound when braking, which is quite normal. The braking system of a new car is still in the break-in period, and this can happen for the first few hundred kilometers. Both the brake pads and rotors are brand new, and their contact surfaces aren't perfectly smooth yet, which can cause minor noise when they rub against each other. Don’t worry too much—it's a common phenomenon, just like getting blisters from new shoes. I recommend driving gently for a while, avoiding sudden hard braking, to let them naturally wear in and adapt. If the noise is too loud or persists, there might be an issue, such as uneven brake rotors or dust trapped in the system. In that case, it's best to have it checked at the dealership. After all, brake safety is nothing to take lightly, and it’s convenient to get it fixed for free during the new car warranty period.

[McEliza]

I just bought a new car, and there's noise when I step on the brakes, which makes me nervous. After consulting professionals, I learned that during the break-in period of a new car, the brake pads may not be fully seated or there could be slight material inconsistencies causing this. Sometimes, damp weather or residual moisture after washing the car can also lead to temporary noise. The solution is to drive patiently for a few hundred kilometers, and the noise usually diminishes. If the noise remains sharp or is accompanied by vibration, it's best to get it checked early to prevent real issues. Safety first—don't ignore small signs.

[Yarrow]

From a technical perspective, brake noise in new vehicles is typically related to the initial break-in period. The uneven surface roughness of new brake rotors and pads can cause resonance and generate noise during friction. Certain design materials, especially those with higher metal content, are more prone to producing sound. After normal driving for a period, as the rotors and pads smooth out, the noise will diminish. Abnormal sounds may indicate foreign objects lodged in the system or imprecise assembly. A professional inspection can help eliminate potential hazards.