What could be a symptom of air in the brake lines?

A soft or spongy brake pedal is a classic symptom of air in the brake lines. When air gets trapped in the brake fluid lines, it compresses more easily than fluid, which leads to a decreased ability to transfer force from the brake pedal to the brake calipers or drum brakes. As a result, the brake pedal feels less firm and may sink further toward the floor when pressed, indicating that the braking system is not functioning properly.

This symptom directly correlates with the presence of air in the system, as the brakes rely on hydraulic pressure to function effectively. If the brake pedal feels soft or spongy, it is essential to bleed the brakes to remove the trapped air and restore proper function. Understanding this characteristic helps technicians diagnose and address brake issues more effectively.