Brake pedal goes down midway and car has no leaks anywhere.

What is your question?

When i brake it goes down half way and if i hold it goes down further. After first pump it fixes and brakes normal. Could it be the master brake cylinder going bad?Old lines look fine no leaks anywhere. No bubbles and fluid is full as well.

What makes this problem better or worse?

Driving it and braking.

How long has your 2008 Subaru Impreza had this problem?

1 week