A-mac

Ok i have a 94 cherokee 4.0. the air didnt work when i bought it but the guy said it just needed to be charged up like everyone else that is going to try to sell something without air lol. Well i got home and pull the header panel off just to find that the condenser coil is gone. I bought one useed and when taking the upper nut off the coil it brought the threads off with it will i figured they had JB welded it or something. So i just bought another used one and the exact thing happened to it. Is there a special way to remove this nut or do i just have really bad luck. Thanks for the help