While bleeding the brakes, there was an air sound when the pedal was pushed?

Hi,

I need you to try something. Pump the brakes up so you have a pedal and then hold pressure on it. See if it slowly goes to the floor.

If it does, replace the master cylinder. I realize there was likely no issue prior, but when the pedal goes to the floor, there can be corrosion in the Master Cylinder which damages the plungers. This is the result.

Take a look at this link. Let me know if you feel the Master Cylinder is the likely issue. If it is, I attached the directions below for replacing it.

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Let me know if this helps or if you have other questions.

Take care,

Joe

See pics below.