HELP my brake pedal goes to floor with new brake booster

[bobfist]

I have everything new, brake booster, master cylinder , brakes etc.
When i apply vacuum to the brake booster the pedal won't come back up.
if i turn off the engine it comes back up!
Tested two master cylinders and check valves, whats wrong!?

If i remove the master cyl the brake pedal goes back...

 

[mr. fix it]

I think that an inspection of the vacuum booster is in order...

 

[commando1]

Check valve.

 

[traintech55]

I had this happen years ago on a 69 Newport. Caused a bad accìdent. Have the rebuilder send you another one.