First to address ccfbailey's concern:
Sounds like the second new caliper is not right. The piston should move freely in and out with relatively little effort. Regarding the amount of air that can be trapped in a brake line, yes, sometimes there can be what seems to be an unreal amount of air.
Now to address BlackBetty06's concern:
You have a brake line leak. Likey one or a combination of the following
a hose developed a leak
a steel brake line developed a leak
the caliper itself is leaking either from the piston seal or where the brake hose connects to the caliper
Good luck to both of you