91 toyota brake problem

Hi all thanx in advance.....Got a 91 toyota and basically i can't seem to get the drivers side FRONT and the passenger side REAR to bleed. I have no pedal and have checked front pads (new) and rear shoes (fairly new) I made sure the rear drums were adjusted and bled the master cyl as well as put on a new drivers front rotor. The pedal seems to build pressure a little while bleeding the fluid doesn't squirt out of the bleeder screws like it should, it just drips. I am guessing it is a diagonal system so would the problem be most likely a proportioning valve? I know the calipers and wheel cylinders are not seized and while on 4 jack stands and pumping i can see and feel them move it just seems like air in the system or fluid getting past a seal in MC.........any suggestions?

Well you should start bleeding the portion valve and go to the left rear,right rear,right front and left front. call me tacky but im just going by the book. look for kinks... but listen to other peoples opinion first before doing anything.