Having trouble with the bleeding of my brakes on my 68 frt disc rear drum. Installed a new combination valve as part of my brake upgrade (basically new stock parts.) Had trouble bleeding the rears. Mentioned this to another tech and he stated that I need to depress the pin on the valve while I bleed. It was my understanding that these were set and were not to be messed with. Curious who's right. Right now though I know I have air in the lines but want to be sure I am bleeding correctly. And i'm using the RR,LR,RF,LF technique.

If you have bled the front out the pin could have over-centered due the pressure difference. Sometimes the pin mut be pushed back untill the rear have been bled out. You could also avoid this problem by vacuum bleeding your brakes. hope this helps.

That's actually what i used at first. Craftsman's version of the mityvac.Got a trickle flow to the wheels with the vacuum. When i removed the hose, it would start leaking out like it was fully bled. Yet when you bled with pressure, very little flow. Anyway, i'll try adjusting the pin to see if that helps. Also, is the pin supposed to stay in? How far? Or do you hold it in. Went flush with the body of the valve and would push out whenever you hit the brake.