Air Venturi Avenger leak (found the leak)

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DeanB

DeanB

Member
Sep 3, 2022
549
681
Rockville, In
Anyone out there work on the Avenger, just bought one here off classifieds and its leaking.. tried to find leak with soapy water but no luck.
Its leaking about 1300 psi in 15 hrs or so, cant hear a leak anywhere either. While I can tear down/tune my springers I don't know enough about pcp to feel comfortable tearing them down.
I did try dry firing gun multiple times so will see if that helped.
 
DeanB said:
thanks for all the info, put plastic bag over end of barrel taped tightly will see what happens.
Someone suggested to me to dunk it in a tub of water(check for leak) then blow it dry with airgun when done, anyone ever tried this? Seems like a bad idea to me.
Click to expand...

Last resort when you ultimately are chasing tail looking...

Strip the gun of all parts minus whats necessary to hold air in the tank (gauge/fill adapter/valve screws ect).

-Matt
 
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you can use soapy water on a sponge to check for leaks, many times it is the fill port valve that leaks, you can replace the fill port O-ring , I think the Avenger has a Fosters fitting, usually there are small #006 O-rings in the Fosters fittings, you can match up O-rings at Ace hardware, they carry a good supply of Buna 7 O-rings, also Make sure the Bleed Screw is tight, many times people drain the air out because of shipping restrictions on pressurized Vessels, I've had this happen on several occasions.
good luck
 
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Hmm, well a leak that repeatably comes down to a certain pressure and stops is usually indicative of an O-ring that is beginning to experience extrusion failure. In other words, at high pressure the elastomer stretches into the gap between the parts and thins out, allowing air to escape. As the pressure falls, the elastomer begins to relax and form an airtight seal again.

But with that said, I don’t have high confidence that is what is happening here because you describe a leak that overnight comes down to 3000psi and stops there every time. Marginal extrusion failures have always been slower leaks in my experience, starting with a high-ish rate of loss when the reservoir pressure is highest but then coasting down to a very slow rate of loss. So the symptom you describe doesn’t match my expectations exactly, but it's the only type of leak I’m aware of that behaves this way so still the most likely explanation. Maybe it’s possible the Bourdon tube of the pressure gauge can behave this way but I don’t think so. Whereas a poppet leak at the valve seat behaves exactly in reverse…may seal at high pressure but leak at lower pressure.

[edit] I was typing when you posted about it potentially being the fill port. That’s a distinct possibility because the O-ring travels each time you fill, giving it an opportunity to seat differently each time it closes. So although right now the leak appears to be far too slow to explain the overnight air loss you had been describing, the rate of loss may wax and wane on account of the check valve cycling.
 
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Well found the leak, it is leaking around the regulator adjustment screw.. 1st time I checked water must not of been soapy enough.
Now how do I go about getting to it to fix it when seal kit gets here, anyone have any links to videos that show this fix?
Does the adjustment screw have a oring underneath it and if so can it be removed to replace it after degassing gun?
thanks for all the help.
 
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DeanB said:
Well found the leak, it is leaking around the regulator adjustment screw.. 1st time I checked water must not of been soapy enough.
Now how do I go about getting to it to fix it when seal kit gets here, anyone have any links to videos that show this fix?
Does the adjustment screw have a oring underneath it and if so can it be removed to replace it after degassing gun?
thanks for all the help.
Click to expand...
It is easy to take out the regulator. First, break the allen head screw loose in the middle of the plenum right next to the regulator. Next, drive out the cross pin with a 1/16 drift pin. Next, unscrew the regulator until it comes out. That is all there is to it. Make sure you use silicone grease on the orings when you install them.
 
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