Bleeding front disc brakes '82 K20

[akart]

New calipers and pads. Have clear hose attached and in jar of fluid.When I crack the bleeder, no peddle pressure. I get bubbles in the line as if air is leaking past the bleeder treads. I am an old guy and have bled many many systems and have not seen this before. These are coarse threads and the rebuilt maybe loose in the threads. So I am thinking of putting some Teflon tape on the threads. Any thoughts on the subject. Would be a real PIA to change out the caliper. Thank You