Bleed front brakes. No pressure.

[alexpski]

Hello everyone. We really love our vans don’t we?
Asking for some advice on my front brakes. I replaced the calipers and my brother came over To help me bleed them. I have brake fluid flowing unobstructed all the way through and out the bleeder screws on both sides. According to the service manual the master cylinder is set up to feed the front and rear separately. Besides, the rear brakes are disconnected via the removed proportion valve (next project).
No leaks anywhere under the van.

Now that the front lines are bled, the calipers aren’t closing on the rotors. The hubs spin freely w the brake pedal down all the way to the floor.

We’re scratching our heads. I’m wondering if there’s a problem with the master cylinder?

anyone encounter this before and can advise? Thank you.

[Headhunter38]

how do you have the rear disconnected? maybe some air got in when you disconnected it

[alexpski]

Bad proportion valve. Removed to replace. The master brake cylinder is on 2 “circuits”. Front and Rear. Separate from each other. Worked beforehand w/o proportion valve.

[Jan-Willem]

11742
If all the fluid has been drained, and there is air in the master cylinder/line to the rear brakes, you would still have a soft pedal.
there are two pistons in the master cylinder, but they are not connected by a rod, but by hydraulics (see picture), and a spring.
if there is air in the rear circuit, i think it may be easier to compress that air, than force brake fluid through the primary circuit. i think i’d try to bleed that line to the rear, before replacing/rebuilding the master cylinder.