ASE Brakes Certification Practice Exam 2025 – Complete Study Resource

A spongy brake pedal typically indicates that there is either low brake fluid in the braking system or air trapped in the brake lines. When the brake pedal feels spongy, it suggests that the hydraulic pressure required for effective braking is not being properly maintained.

In a braking system, hydraulic fluid transmits force from the brake pedal to the brake calipers. If the brake fluid level is low due to leaks or other issues, or if air has entered the system (which can happen if there are any leaks or if the system is not properly bled), the result is a loss of pressure and a spongy feeling when the brake pedal is pressed. The air compresses, leading to a “soft” pedal that doesn't provide the firm feedback drivers expect when braking.

Proper diagnosis and remedying of these conditions—either by topping off the brake fluid or bleeding the brake lines to remove air—is crucial for the safe operation of the vehicle's braking system.