You need a special double flaring tool to do the lines - the normal single flare tool will not do the job. And even with the tool - it takes a bit of practice to get them to come out right consistently. It is a lot easier to use the tool on the bench than it is under the fender of the car on the end of the line in there.

It is well worth spending a few hours with penetrating oil and careful working back and forth of the nut than to try to repair a broken line.

For the tubing fiting wrenches - here it is worth avoiding the old dependable Craftsman wrenches - they are not thick enough and will spread enough to round the nut. Buy a good professional set - they will work a lot better, and even though they may cost more than the Craftsman or other inexpensive brand, if it saves you one or two fittings, they are well worth it.

If your car is more than 10 or 15 years old, check those ruber lines carefully. IF there are signs of deterioration, or if you can feel the line expand at all when someone steps hard on the pedal, then it is time to replace. I usually opt to replace with the stainless braid lines - they are about the same price as a complete set of Volvo hoses. --
Steve Seekins,