Do you know anyone you can borrow/rent a power bleeder from? I bled my last one that way and was successful the first time. It is also important to have all of the shoes adjusted up. I have even tightened them up to the point of locking against the drums before so I know whether or not I'm dealing with an air or an adjustment problem. Also, if it's a new master, your pedal to master adjustment may be off too,
Good luck,
Scott

Scott Ward

2 1948 1.5-ton Loadmasters
The red one and The snow pusher
1 1950 3100
1 1955.1 Chevy 6500
1 1954 Chevy 6500 2-Ton
1 1955 1st Series COE 5700
1 1963 K20 (454)
1 1964 C10 (350)
1 1951 1.5-ton Dump Truck
1953 and a 1956 Ford F800

Raising a teenager is like trying to nail Jello to a tree!