http://www.henkelna.com/adhesives/produ ... 7960863745
or this stuff
http://www.henkelna.com/adhesives/produ ... 7881991169
Just put it on the tapered seal face, not on the threads and don't use a lot. Tighten normally. Give it about 30 minutes or so before vacuum and fill.
I would only do the joint that is leaking if time is a consideration, you never know what can go wrong when you are pushed for time
