Classic/Antique Car Repair: Brake problem, bleeder screws, rear brakes

Question
I recentlt installed an OEM master cylinder on my 1966 Chevy C20 truck. I went to bleed the brakes and can only get fluid out of the front brakes. I broke all the lines loose to the rear brakes and have no sign of fluid getting to the rear. The master is a single resovoir one line piece. I replaced the line going from the master to the tee block. Any help will be appreciated.

Answer
There are several probable causes. The bleeder screws may be plugged up with dirt and rust.   I have had to take bleeder screws out and clean out the passages with a small drill. If the bleeder screws are clean and still no fluid check the line from the "T" block to the rear wheels. Loosen the line from the "T" block to the rear wheels and check for fluid coming out when the brake is depressed. If you get fluid head for the next connection and recheck, checking all the way back to the wheel cylinders. The most probable cause is that the flex brake line from the frame to the rear axle may be coming apart internally and blocking the flow of fluid.