There's two problems with the connection you're referring to. The nut gets rusted to the steel line and the nut gets rusted to the brass fitting on the flex hose. The way I always got those free was to heat the nut with an acetylene torch. Use safety glasses and wear old clothes. The rubber is going to soften and squirt out of the crimp with a loud pop and lots of neat smoke. By that time you'll be able to work the nut loose in the brass fitting. Be sure to use a flare-nut wrench, (line wrench) on the nut to prevent rounding it off.
Once you get the nut free in the brass fitting you can remove the clip that holds the fitting to the bracket, pull the fitting down out of that bracket and unscrew it from the nut. Now heat the nut again to expand it, then use the wrench to work it free on the steel line. It's coming free when you hear it squeaking. Don't use any type of penetrating oil or any petroleum product anywhere near where brake fluid can come in contact with it. That will destroy all the rubber seals and o-rings in the brake hydraulic system. As it cools down, spray the nut with Brake Parts Cleaner as you work it back and forth to free it up and wash the rust out.
Tuesday, August 6th, 2013 AT 1:19 PM