My Tanks leaks

[abrewin450]

I have a crossfire 45 ci tank. My problem is that occasionally air will leak out of my fill port nipple. I took it off and saw that the o-ring had a little cut in it. I think that is the problem. I tried to fix it by putting it in hot water so it would expand and make a better seal. It works sometimes and doesnt others. I figure i just need to get a new o-ring for the little "stopper" piece but I don't know where to go about getting one. I noticed that they had o-rings on the airgun website under parts for the flatline but I dont know if they are for the same thing. Please let me know if you know what I need. Thanks

[xen_100]

go to your local hardware store and get a replacement. most stores have a decent selection. jsut make sure you take the fill nipple check valve with you to size the o-ring.