Odd rear brake issue, any ideas?

Has anyone ever had issues getting a mustang rear caliper to compress when changing pads?
On my car, it absolutely will not let me compress the caliper far enough to fit semi new pads unless I disconnect the line. I've tried opening the reservoir cap and opening the bleeder valve but it didn't make any difference. Even tried a new set of calipers, same thing, it stops about 2 turns early and can easily be turned the rest of the way in once you disconnect the line.
And yes, I'm using the correct caliper return tool that turns the piston as it pushes.

I had this problem an I just tightened it back an then immediately tried loosening it an it worked


Sent from my iPhone using the svtperformance.com mobile app

I actually discovered the problem to be my aftermarket stainless brake lines. The banjo bolt was going in just a touch too far. Swapped back to stock lines and they compress just fine.