What is an example of a condition that can lead to a soft brake pedal?

A soft brake pedal often results from air in the brake lines. When air becomes trapped in the hydraulic brake system, it compresses more than the brake fluid does under pressure. This can lead to a spongy or soft feel when the brake pedal is pressed, as the air bubbles absorb some of the force that would otherwise help create the necessary stopping power.

In a properly functioning braking system, the brake fluid transmits force from the pedal to the braking components without any compression. When there’s air present, it disrupts this hydraulic pathway, making the pedal feel less firm and potentially compromising the vehicle's braking effectiveness.

Other conditions, such as system contamination, worn brake pads, or low brake fluid levels, may present different symptoms or issues. For instance, contamination could lead to poor braking performance, while low fluid levels may trigger a warning light or cause other operational issues, but they do not specifically lead to a soft pedal feel as air in the lines does. Worn brake pads may lead to decreased performance or noise but do not directly contribute to the sensation of a soft pedal.