What is defined as "squeal" in a braking system?

In the context of a braking system, "squeal" is specifically characterized as a high-pitched noise that occurs primarily due to the vibration of brake pads as they engage with the brake rotor. This sound typically arises from the resonance created by friction between the brake components, which can be amplified by various factors such as the material composition of the pads or installation issues.

The high-pitched nature of the squeal differentiates it from other noises that may indicate problems with the braking system. For example, grinding noises suggest severe wear or damage to the brake pads or rotors, while vibrations felt through the steering wheel might signal issues with the alignment or balance rather than the brakes themselves. Similarly, noises occurring at high speeds may not specifically relate to the brake operation but rather to aerodynamic effects or other mechanical components of the vehicle.

Thus, the definition of squeal as a high-pitched noise due to pad vibration correctly identifies the specific condition associated with brake performance and maintenance concerns.