That is the most knowledgeable thing you have said during this whole thread.
Go to advanced auto and ask them for A/c dye. Get you paws on a UV light so you can see the dye coming out. There is no soldering, welding, mechanic in a can. Second, you do not have to replace the dryer just because there is a leak. If it's a seal you evacuate the existing freon, replace the seal, and recharge the freon.
How exactly did you recharge it? Were you reading the amount of Kgs that you were putting in and the pressure? Or did you go "backyard" mechanic on it?
