Brake Booster noise

[9teen69]

History: Disk/disk setup, Booster/master cylinder from CPP 4 yrs old (previous owner installed), new disk/disk prop valve. Rear disk conversion last year. Just installed new hardlines front to rear, new front rubber lines, new calipers and rotors.

Brakes still seem mushy, one pump seems to help but multiple pumps have no effect. Not much better than before the rear conversion. Can't stop the vehicle fast and barely can lock it up.

I have replaced all fluid and bled bled bled, pumped out all old fluid prior to hard line replacement last month.

Today I checked the check valve and it fell apart...brittle. Hoping that was the problem...nope.

So i replaced the grommet, check valve and 3/8 line. No change except it now makes a popping noise when I turn the motor off.

Getting lots of vacuum from motor and also getting the rush of air when pulling off check valve from booster.

What am I missing? Think my master is bad?

Here's the video of the booster noise:
https://www.youtube.com/watch?v=_I5IRF_LzhY

Picture is a few weeks old but shows my setup.

thanks