Request mechanic tips

I assume you're referring to the pressure and return lines at the rack. If the return line is stuck, look if the rubber hose is attached about a foot away. Just slide the clamp off, then slide the hose off and take the metal pipe with the rack. If it's the pressure hose you might be able to remove it from the pump and squeeze it out with the rack. If you don't need the hose in question, you can cut the pipe with a hack saw or side cutter, then use a ratchet with a six-point socket to remove the soft metal nut.

WD-40 might work if you have a long time but the best thing I've found is "Rust Penetrant" from the Chrysler dealer's parts department. I've hear "PB Blaster" is good too.

You can get away with heat from an acetylene torch but keep the flame really small. I don't think a propane torch will get hot enough but you can try it. First heat the nut, then cool it quickly with a few drops of water. That will shock it and help the threads come loose. Once you have the threads freed up the nut will usually be corroded to the steel line so don't keep turning because that will twist the metal line. Now heat the nut again and work it back and forth to free it on the pipe. Spray some brake parts cleaner on the nut and pipe. If you can back the nut out a good half a turn, that will make some room to pound the pipe in toward the rack. Look for a mounting tab welded to the pipe. You can tap on that to drive the pipe through the nut to start freeing it up.

You can use the Rust Penetrant on the pipe too, but once you get everything apart, use brake parts cleaner to clean the pipe as you spin the nut on it. Also be sure to wash off all the Rust Penetrant. It works really well by sneaking into all the cracks, but that opens the way for moisture to follow it in. That will make those parts even more rusted together in the future.