Problem solved!
I backed off the pistons, it only took about 1/4 turn, if that. I made sure that the calipers went on nice and snug and I had brake pedal and the e-brake works better than it has since I bought it (used).
I was a little concerned that there was a little bit of drag when I turned the wheel, but it seems to be OK. The van coasts fine.
Hope this helps anybody with the same problem. Thanks to AndrewG for the help.