Bad Master Cylinder or Air?

I had a lot of trouble bleeding my brakes when I did the KH swap on the wagon. I ended up using a Phoenix Injector, which pushes the brake fluid from the brake end backwards to the master cylinder. That worked very well.

I borrowed the tool from my dad. I gave him endless **** when he bought it, because I thought it was a gimmicky waste of money. He still asks me weekly how his gimmicky tool worked out.