FIRST THING you MUST do is get the system air/ liquid tight
Personally I DO NOT LIKE vacuum bleeders, and the reason might be related to your problem. If you pressure bleed, and that is WHAT the system normally sees, any leaks will tend to show up. Plus you will not be sucking air into the system. Wheel cups can ingress air under vacuum.
Many people have good luck with gravity bleeding.
For any vehicle I've ever bleed, I've been able to lash up a cap for the master and create a pressure port. For a recent Dodge Dakota, I bought a new cap and epoxied a tube into the cap Some guys use an old weed sprayer bottle for pressure
