I just pulled my rear brake lines this weekend. Yesterday, couldn't budge them - they were rusty where the line met the fitting. I sprayed kroil on them and tried today. I got them turning & off on the wheel cylinder side with a vise grip. Once I got the end at the cylinder off, I was able to slice a wrench over the fitting and down to the other fitting. If worse came to worse I figured I could cut the line to allow me to slide the wrench on, but didn't need to. A couple of wacks with a hammer loosened the fitting. I think the soaking 24 hours with lots of kroil helped.
