If the lines cracked where they are welded to the end that bolts to the condenser, take them and have them welded again. Ours cracked at this point about 2.5 years ago. The a/c shop sent them to a welding shop who repaired them for us. They have been fine every since. Better welds than the factory puts on them. Another piece of advice, if you are at a dealership its no wonder they want to replace instead of repair. A/c is a/c, vehicle doesnt matter. Take it to good a/c shop. Thats all they do. You will get much better service and a/c shops are all over the place.