Trouble bleeding rear brakes

[JimZRyd]

Hey guys! I'm attempting to bleed the brakes on my 94. Starting with the right rear. I've got new calipers from Mid America, stainless lines and speed bleeders from Russell. Using a Motive pressure pump AND a Mighty vac. I can barely get any fluid flow. When I open the bleeder screws I will get about an inch or so in the tube but that's it. I wait about 5 minutes and the tighten the bleeder back down and check the Motive pressure, pump the brake pedal a couple times, feels firm, and then go crack the bleeder screw again and all I get is just a trickle of fluid. I've removed the bleeder and it still trickles. I disconnected the line itself and get flow, not a lot but it does flow.

Am I not giving it enough time? I've bled many a brake, even Corvettes, and always had steady flow of fluid during my bleeding process. This is the first time I've tried a C4. Could I have gotten some sort of air lock? I'm stumped! Any advice will be greatly appreciated! TIA!!