Pinpoint Test E: Excessive Brake Pedal Travel (Low/Spongy Pedal): Notes

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Normal Operation and Fault Conditions

The brake pedal is connected to the power brake booster, which is connected to the brake master cylinder. When the brake pedal is pressed, brake fluid is pushed through the double-walled steel tubes and flexible hoses to the front and rear disc brake calipers. The brake fluid enters the disc brake calipers, forcing the caliper pistons and brake pads outward against the brake disc friction surface, slowing or stopping rotation. When the brake pedal is released, brake fluid pressure is relieved, returning the front and rear disc brake caliper pistons and brake pads to the unapplied position. Leaks and/or air in the system can cause a spongy brake pedal and loss of braking in the vehicle. This condition indicates there is a concern with the brake system.

Possible Sources

Brake fluid leaks and/or air in the system
ABS / HCU
Brake calipers and/or guide pins
Brake flexible hose