rear brake problems
 

Hey guys, new to this forum so a quick intro. I am retired and have no money and no time so I need some free advice. I bought a 1974 camaro new in 1974 and it has been garaged for the last 15-18 years. Only start it up occasionally and back it out of my shop and let it run for 30 or so minutes and then pull it back in. I know this is not enough but as I stated earlier, no time or money. Anyway, my grandson is turning 16 in a couple of years and he wants it for his first car so all you grandparents out there know what I have to do. First problem is the brakes, (none), so i replaced the master cylinder, combination valve, rear shoes and cylinders. Bench bled the master cylinder and still can't get anything but a LITTLE air bubbles out the rear cylinders. Opened the right rear bleeder screw and took top off of master cylinder overnight with nothing out of bleeder hose the next morning. Have tried holding the pin in on combination valve and only get a little air bubbles. What am I missing? Thanking you all in advance.