No brake pedal pressure?

Here's an update on the brake situation. I ran the adjustable pedals up-and-down and there definitely was a difference when the pedal was higher off the floor. The pedal pressured up 4 to 5 inches off the floor. I understand it really didn't change the travel of the piston at all. It just gave more clearance to push the brakes. However, when I was pushing hard to see if the inner seals were holding, my plug failed so fluid came flying out the rear port. After that I hooked the lines back up and was unable to get any pressure in the system. Even though I did ABS auto bleed and 4 corner bleed. So, I removed the master cylinder and put it in a vice to bench bleed it and was unable to push the piston in more than a quarter inch. Then I took my plugs out of the side ports, and I was able to flush the cylinder and push the piston all the way in. So tomorrow I'm going to bench bleed the master and reinstall it on the car and see where I'm at. My friend who is a certified mechanic also says every time he puts a line on an ABS block or replaces a block, he has trouble bleeding the system. He says you need to crack the lines one at a time on the block and have somebody pump the brakes. This will not be possible as I said earlier. I believe the lines will crack. I am really at my wits end with this system. The reservoir was filthy with dirt and possibly deteriorated rubber. I believe the master is good because before my makeshift plug blew it was holding firm. Have you heard of bleeding the master by running using plugs with lines attached and pumping the fluid right back into the reservoir?

The problem is there's no clearance between the body and frame like there is on a pickup. Is it necessary to open all the lines on the controller?

Bench bled master again, then bled master installed. ABS autobleed, four corner bleed. Truck has brakes. Seems easy to push pedal but with the Hydro boost and electric assist I guess it would be. Master didn't bleed on bench the way I'm used to. Fluid ran through ports but when blocked the piston wouldn't move all the way in the first time or two. Then I made a makeshift plug with a hose attached and ran that into the reservoir and was able to push the piston all the way in each time. Only was able to do the front port this way. There's still probably some air in the system somewhere but I did all I could.

Yes on to the next project, lol.