If you are replacing the wheel cyclinders and not rebuilding them, heat is your friend. Take a common propane torch and heat the tube nut up. It doesn't have to be red hot or anything drastic, just heat it up. While it's hot, hit it with Kroil, PB, any penetrating oil you like. Try to move the nut. If you get to the point of refusal, back off and re-do the heat and penetrating oil thing. I've save numerous brake lines like this. Now be aware that the cloud that comes off the hot fitting from spraying it with penetrating oil is flammable. Turn the torch off. Good luck.


As a side note, when I go back together I CAREFULLY put anti-seize on the tube where it passes through the tube nut and on the tube nut threads. Want to get some protection here without contaminating the brake fluid.