Wire brush the rust off the exposed threads. Use a torch to heat the nuts, and turn them while hot. Have all your tools within reach and be prepared to work fast! If you delay long enough that the stud becomes hot, let it cool completely, then reheat the nut. Never try to turn the nut while the stud is hot unless you want to break it off.
To remove a stud or screw from a casting, heat the stud or screw immediately adjacent to the casting until it is red hot. Then let it cool to room temperature. This process expands the threads, which are constrained by the cooler casting, distorting them. After it cools the male thread will be slightly smaller and generally spins out easily. If you want to use penetrating oil, do it during the cooling stage; the oil will become heated and less viscous, and will be easily drawn into the thread. If the stud still won't turn, try heating the casting surrounding the stud, but not the stud itself.
Heating the body of a brake caliper or wheel cylinder immediatly surrounding the bleeder will allow the most rusted bleeder to easily unscrew. After its heated use a 6-point box end wrench to apply torque while simoltaneously tapping the wrench with a small hammer to provide impact. Don't even think about using a 12-point tool- it *will* round off the flats. By using this method I haven't broken a bleeder in ~20 years.
Acetylene torches work better than propane.
Ken
