fill it, than dunk it in a bucket of water, tell us where you see bubbles coming from. if it's the ports where the guage or fill nipple are, use a wrench to get it out, and reseal it with new teflon tape. if its from the guage itself, replace it. if it's from the inside of the fill nipple (where air would go in) take it out, remove the strut and replace the oring on it. If its from the safety, try to tighten it if thta doesnt do it, buy a new one. if it's from the asa, than it needs to be taken apart, bring it in. if it's from between the tank and the reg you need a new oring, best to take it in. if it's from the bottom of the bottle, RUN LIKE HELL.
If you have a problem with your Air system, post it, I'll try to help you with what you need to do to fix it, and where you can go to get parts. AAchopshop is now open on ebay http://stores.ebay.com/AA-Chopshop?refid=store