Bad master cylinder?

[J-440]

Evening all. Had my rear brakes go out all of a sudden. Front brakes are fine. I drained the entire system, replaced with new fluid, did a one man brake bleed with a Mittyvac. I know you're supposed to start with the passenger rear and work your way up. I started to do that and I got nothing from the caliper. Unscrewed the brake line fitting from the flexible steel line, pumped the brakes manually and got no fluid at all. I walk up front and check the fluid in the 2nd reservoir from the MC and it's full. I go to the driver side rear, do the exact steps, and get the same results...no fluid. I do both front brakes and I'm good to go making sure no air gets in and the 1st reservoir is topped off.
Wilwood says to bleed the outer screw first, then the inner but I still get nothing from both. Am I missing something? Thanks.