Just bought this used and have started working on it.  

Front brake cylinders are rusted and in rough shape.  I have taken lines off and blown them out.

Master cylinder appears to be working, because I took the line off of it, covered the hole, and pumped the handle.  It built pressure and sprayed fluid everywhere.

However, with everything hooked up, brake handle can be pumped and will build no pressure.  Can't even get fluid coming out of bleeder valves.  

What could be causing this?

Thanks  

if you have everything hooked up fill master open bleedr screws on wheel cylinders it should start to drip after awhile.then close bleeders pump handle and hold it depressed while you open one bleeder at a time leaving the handle dpressed until the screw is closed,repeat procedure several times.if you have a hand vacumn you can attach it to the bleeder screws one at a time making sure the other is closed,also make sure that the brakes are adjusted properly before starting out other wise you will never get good brakes.