at least one rear gives a solid fill on the pump - I don't recall on the other. The front simply gives a trickle.

Top off the master, get somebody out there with you...

Pump 'em up and crack a front bleeder...

If you've got good flow to the wheel cylinder, but little out of the bleeder, that really only leaves the wheel cylinder...

Are the bleeders clear???

I have a power bleeder, no need for 2 people. Bleeders pull fluid just fine when tested, issue somehow must be with the wheel cylinders.

Hope you're positive of the adjustment. The shoes need to ride pretty close to drums or pedal will be low.

When I rebuilt the 11" manual drum brakes on my '69 Coronet, I got the springs and self adjuster kit for the '70 model to get rid of the manual adjusters.
I hope you bench bleed the master cylinder before installing it.

Adjustment seems good and it was bench bled. I've manually bled it a few times since the issue and its better. Not perfect, but better and driveable.