MC lid ON...unless you like cleaning brake fluid off of everything under the hood....

So....if you disconnect the line directly from the MC itself and blow thru it, you get flow to the rear??? This is before the P valve, so if that is correct, then the P valve HAS to be centered....there would be NO flow if it weren't. That can mean only one thing...the Master is faulty.
Try this, if possible. SWAP the lines on the MC, and see if you get fluid to the rear...if you do, then the master is definitely the problem. I say "if possible" because the fittings on the front/rear lines may be a different size, so you may not be able to do it, but it's definitely worth a try.

Joel, I will try switching lines . It is a new- reconditioned MC. But yes I get air to the rears by blowing air in upstream of the PV , From disconnected line at the MC fittings are same size Thanks, AL UPDATE NO FLOW FROM REAR MC unit.. Tried even to get anything out of the fitting .Like stepping on pedal and hoping for a squirt all over fender well. ANOTHING. Nada. Zilch . Funny when I bench bleed it , the hose ran full of fluid. Now nothing. . OH well what's another trip to the parts store. Will do tomorrow and let you know what happens . AL

|UPDATED|7/24/2013 11:39:01 AM (AZT)|/UPDATED|

Probably a stupid question but was the cover off the MC when you tried gravity and vacuum bleed? It would stop bleeding when vacuum built up in MC with the cover on.

Cover off ,engine off and power brake check valve removed . My last post is returning MC as no flow is coming from rear compartment . Frustrating , but a labor of love and hate. AL

Well it sux you got a bad MC, but good that you got it figured out. Be sure to bench bleed the new one before installing it. 

Will do and I'll keep you posted. Tried to loosen the line on the PV But no luck or I'm weak AL

I replaced lines from MC to PV and couldn't get lines off PV even with a 6 point line wrench...Had to remove PV and clamp in vice and use vise grips on line to remove

UPDATE. Another new reconditioned MC, bench blend according to MFG suggestions. Installed. Gravity bled fronts all ok Backs needed a little vacuum to get flow started . Then used pump and release to make sure alls well. ALL ARE NOW BLED AND fluid at all bleeders and no bubbles. YES WE HAVE COMPLETED THE BRAKES NEXT PROBLEM T /T. HORN . THanks all AL.