2015 soft brake pedal after caliper replacement

[mountainbikeak]

Looking for some advice on bleeding brakes on a 2015 limited.
I was changing out my brake pads/rotors and came across a rear caliper with a seized piston so decided to just go ahead and change them all out (front and back). I made sure to check fluid levels and not allow to drop below half while changing out calipers.
After bleeding the brakes multiple times the pedal is still soft after starting the truck. It’ll be a bit firm at first but as I keep pressure on the pedal, It’ll slowly fall to the floor. With the truck off, the pedal is firm. All calipers are in the correct position with bleeder above the brake line and no visible leaks.
I originally tried the one person method with a bottle and hose through the cap submerged in brake fluid. After that didn’t work, I was concerned My hose connection wasn’t great (even with a zip tie) so I had my wife help and had her pump while I open and closed bleed valve (as per instructions on the internet).
Does anyone have a tried and true method for bleeding brakes? I have a trip planned for the weekend I would hate to cancel because of a simple brake bleed issue.
Everything worked before, besides the seized piston.

Thanks.

 

[Tremper126]

There’s a method where you engage the abs pump and then follow bleeding procedure. I had to use this method on my dads 06 2500 chevy. I got soft brakes after doing pads and rotors on the rear of my 2014 1500 ram, still don’t know what caused it, the only assumption is the rubber internally is failing and allowing it to lose pressure from the rubber expanding