cannot get air out of breaks

[autozen]

56W105,
Back in the day when I first worked for Mercedes, I drove a 56 190D. That was an experience. On to your problem. You said you changed the brake hoses, and I'm assuming all four even though that has nothing to do with your problem. Occluded brake hoses will only cause irregular braking. You didn't mention adjusting the brakes. Drum brakes that are not adjusted for wear will give you a low brake pedal. Also if you open the bleed screw too much, you will syphon air around the threads causing you to think there is still air in the lines. I can unscrew a bleeder screw way past cracked open and go through gallons of brake fluid in a day and still have bubbles.