Strange brake issue

[papapavs1]

Hello I recently bought a 1979 Chevy c10 with a 305. When i bought it it had absolutely no brakes. I put two new front hoses on it and got front brakes, but haven't bled them yet. I then had to replace the long rear line (rusted) to get rear brakes. There seemed to be some rear brakes in it but they weren't super great, and I couldn't bleed them due to stuck bleeders. So I replaced the wheel cylinders and bled the rear brakes. I can't seem to get either side to actually move the shoes/pushrod that goes into the cylinder out though. They bled out fine, plenty of fluid coming out with no air, but absolutely no movement on either side. Part number checked out as correct for 11x2 inch brakes. Is it possible I got two bad wheel cylinders out of the box? Bad master? They seemed to work at least a little bit before, right after I put the line on. Thanks

 

[fast 99]

Unlikely 2 are bad suspect a master issue or rear hose.

 

[Dmack]

Probably the proportioning valve got tripped, therefore not letting fluid go to the rear brakes. It should be on the front crossmember on the right side.

 

[Ricko1966]

There's a combination valve below the fanshroud,drivers side. The combination valve blows off center when you have unequal pressures,as in a broken brake line. Research on the web gm combination valve and buy a centering tool. Just buy the centering tool now you're going to need it. Do your research while the tools on its way.