What does a "soft" brake pedal indicate?

A "soft" brake pedal typically indicates a problem with the brake fluid or the presence of air in the brake lines. When the brake system contains air, it compresses more easily than brake fluid does, leading to a spongy feel when the pedal is pressed. This sensation occurs because the air can create voids where the hydraulic pressure isn’t effectively transmitted to the brake calipers, resulting in decreased responsiveness.

Proper brake function relies on an incompressible fluid filling the brake lines; even small amounts of air can disrupt this hydraulic system. Additionally, low brake fluid levels due to leaks or deterioration can contribute to a soft pedal feel. Therefore, when experiencing a soft brake pedal, it's essential to check for air in the lines or issues with brake fluid, as these are primary causes of this problem.

The other options, while related to braking issues, do not directly explain the specific symptom of a "soft" pedal.