I am applying new calipers to my 79 ranchero. I cant seem to get the brake line off of the old caliper. Is there a trick? Every time i unscrew the nut connecting the two it screws back by itself. Can anyone help?

 

If you are trying to get it off the banjo fitting, then it is probably corroded. If the hose is original you might as well replace it and its twin on the other side, and since you are getting wet with brake fluid, might as well change the rear hoses too.
OBTW, there should be areas on it to fit a flat wrench. so you can use two wrenches to take it apart.
Pam