I am bleeding my brakes on a 1970 Roadrunner and i just finished bleeding the rear brakes moved to the front and the fluid will not flow through. tried cracking the line on the master cylinder and no fluid will go through. I actually had the hole line disconnected from the master cylinder and no fluid will go through. Whats my problem here.

did you change anything before this?

You are talking about the rear port in the master cylinder? you opened the line AT the master cylinder and got no flow?

no i didn't change anything. i already bleed the rear brakes and cant get the fluid to come through for the front breaks. i think there has to be something clogged in my master cylinder

did you let it run empty?
you may need to bench bleed it, or plug the port with your finger on the return stroke.

Update. i put some mustard in my foot and kicked the peddle witch unclogged the seeming to be clogged master cylinder now i just gotta solve my stripped bleeder screw on the caliper issue.