Not sure this question is posted in the right area but I'm sure the mods will place this in the appropriate section.
As for your leak the best thing to do is to pressurize the tank using a manometer. Use leak detect solution (soapy water) on the entire wing upper, lower, dry bay, and flap well surfaces. This is the best way to identify a leak. We use this method everyday at the depot. Send me a private message if you have any other questions.