Spongy brakes - 4th gen F-body swap onto 68 Cutlass

[borrone821]

Hi Everyone,
I finally "finished" up my disk brake swap on my 68 Cutlass convertible.

4th gen F-body calipers/rotors/pads, BRP spacers for the F-body brakes, completely new NiCop lines, a 2229NC Booster and Duralast NM1749 Master (disc/disc for 70s corvettes where outlets are on driver side), and a Willwood proportioning valve.

Finally took the car out for a test drive today around the neighborhood and absolutely had to stand on the the braked pedal to get it to stop.... way worse than original manual drums that I took off it.
I know I'm getting vacuum to the booster, pedal feels like booster is working (how it feels when turning car on and off).
With the engine on or off though, it feels like I can push the pedal a lot farther than I should, and with the car off, I can't really build up pressure to the brakes where the pedal point is way higher than when running.

I do know when I bled it I had a b$tch of a time getting fluid through, bench bled the master multiple times, and got solid fluid (no bubbles) at all 4 wheels. Only thing that I know is that when I was bleeding (son in car pushing pedal and I had a clear tube on bleeder going into container) there was solid fluid, but it never actually really flowed into the container like the other brake jobs I've done.



Is that the master isn't pushing enough fluid or fluid fast enough?

I'd rather targeted troubleshooting at this point rather than getting the car back up on jacks (was on them for months) and re-bleeding to get the same stuff.


Thanks in advance
Jim