07 camry. I checked all brakes for leaks. None. Bled brakes. Replaced brake master cylinder. Bled master cylinder. New front pads and rotors. With engine off, pedal is firm. Hold pedal, and start engine, pedal travels almost to floor? Noticed this problem a couple of weeks ago? Could it be the brake booster? Or is there anything else I should check?

 

Typical power brake operation (engine on) results in a lower pedal position with repeated pedal application.

Is the pedal height really lower or is the booster operation not resulting in stepped lowering of the pedal. The pedal now going right to its lower point?

The booster amplifies the brake force.

You followed the bleeding procedure? Bleed master cylinder first? Longest brake line first and working from there?

Does the car have rear drum brakes? If so adjust the shoe position per spec.

The fluid over time can pick up moisture. Replacing all of the fluid often results in a firmer pedal.

 

Firm pedal, with engine off. As I press brake, then start car, pedal will slowly head toward the floor. I can pump it, and it still slowly heads toward floor. Feels just like a have a leaky line or caliper, but I do not. There is no fluid loss from master cylinder. Nor is there any fluid around any wheel or under the car.

 

The booster just assists moving the master cylinder piston.

Block car, E-brake on. Remove front tires.

Have someone press on the brakes engine on, while you watch calipers for excess movement.