leaking rainstorm help

[gtcpa]

Well I got a chrony and was about to use it today for the first time with the rainstorm.

I filled the rainstorm up to the 200 bar mark (maximum recommended fill), and was about to put a magazine in to start shooting, and I heard the  psssssssss coming from the base of the air tube.

I usually only fill the gun to 180 bar, and usually shoot it to about 150 bar till I put it up to shoot again (usually in a day or so).  Since I had the chrony, I wanted to see what the gun would do from the full position.

I took the stock off the gun (very easy to do with only one screw holding it), and looked at the area where the leak was coming from.  It is in fact at the base where the compressed air tube goes into the mechanical body.  The leak will take the gun down to about 100 bar.

I have tried to find a diagram or schematic on a rainstorm, but am having a hard time locating one.  Because of this, I am afraid to try to remove the compressed air tube because I don't want to mess anything else up. 

I need help from anyone that may have a rainstorm diagram, or can otherwise tell me what I need to do to remove the air tube, as I assume there is an O-ring that I need to replace there somewhere to repair the leak.  Also, do I need to remove the manometer before I attempt to remove the air tube ?
 

[Filnez]

Here's a link to a thread on the South African airgun forum with several photos of an Evanix Blizzard taken apart.  The Blizzard has the same action and basic parts as the Rainstorm, so this might be of some help to you. 
http://www.airrifle.co.za/showthread.php?s=b9fc446cb4626a4fc1910a37cd35bc6a&t=14139

[bluzjamer]

Than filnez ...I have a blizzard and this will come in handy
Bob

[gtcpa]

Thank you Filnez for your help.  That was a great thread link that is very helpful.  I didn't realize there were a few O-rings down there to check out.