Q: Replaced rear caliper that was stuck. Also changed the rotor and brake pads, now when I step on the brakes, they still go all the

My brakes were going all the way to the floor, after careful inspection I replaced the passenger side rotor & brakepads because they looked terrible. I also replaced my rear passenger caliper, it was stuck out way past where it was suppose to be, due to the rotor damage. I also changed the rotor and brake pads as well. When done, my battery in my truck was dead, I put the truck on neutral, rolled it back a little bit and it still won't stop. Seems like my calipers aren't gripping my rotors...Why? All calipers, rotors and brake pads are now in good condition, there has been no leaks & I had a mechanic come checkout my master cylinder, & he said it seems to be pumping and brake fluid is getting to the caliper, could it be that I didn't properly bleed the brakes? Is that enough to not allow all of my calipers to engage? 04 Chevy Suburban
My car has an automatic transmission.