2005 V70 non turbo, 220K mi. Automatic, Front wheel drive (no Dynamic Stability Traction Control) Newish pads and rotors all 4 corners.

I replaced my master cylinder because my brake pedal was going down to the floor at stop lights and I was not losing any brake fluid. (I used an ATE brand) I bench bled the master the best I could using the fittings and the tubes that return the fluid to the reservoir. I then installed the master and fully bled the breaks twice, starting with the wheel closest to the master cylinder, because this is how my book says you should do it. (I know every other car I have ever had says start with the wheel farthest away)

The car stops very well, requiring not much pedal travel, I even tested the ABS and it works great, BUT if I bring the car to a complete stop and then press down hard on the brake pedal hard, the pedal continues to go down almost another 2 inches. (I know a little is expected but this seems excessive). I tested the breaks with the car in park and motor not running, sometimes they are firm and other times they are mushy (I mean all the way to the floor) it doesn’t change no matter how many times I pump them, they are either Firm or Mushy with the motor off. It almost feels like a lot of air in the line, but this can’t be the case as the car breaks so well while driving. Is there something in the brake circuit that I don’t understand?
While coasting down a hill in neutral with the engine off, the brakes were very firm and required very little brake travel to stop the car.

Today’s test drive: brakes stopped car just fine, but pedal did not feel as firm as it did yesterday, more pedal travel than I remember before brakes began to engage. Still puzzled (or am I over thinking this thing)

 

NEW INFO, i bled the breaks for a third time. I am talking about using 2/3 of a liter of brake fluid, pushing all of the old fluid out of each break line. if their was air in the system it would be gone by now. I did not find any air bubbles in the system during the third bleed and the brakes feel the same.

What does anybody think about the possibility that my rubber brake lines are slightly expanding during full pressurization and causing the mushy feeling in my brakes?

Please remember that the car stops extremely well with very little break travel, but after that i can still push the brake pedal down another 1 1/2 inches if i stand on the brake pedal, it doesn't go down slowly, it goes down linear as more pressure is applied. I don't remember my other cars acting this exact same way, but i borrowed a friends brand new Honda and it acted similarly, but the pedal didn't go down as much as i stood on it (it felt firmer).
One more thing, if there is no vacuum assist the pedal does not go down like this. it is hard a a rock...?

 

You may be losing a certain amount of "boost" from the master cylinder causing the brake pedal to drift a bit.

If in doubt, have the dealer look at it.