Tuning AF Texan - Fill Port Locks Open

[scallen2112]

Hi. I have a problem with my Air Force Texan CF. The plastic cap for the male foster fill port was lost in the woods, and I think I may have gotten some rust or something in the port from hunting in the rain. In any case, it has started locking open. When I fill the gun, it sometimes takes exceeding current tank pressure to open it, and you can hear it snap open. Then, when I am done and go to bleed the fill hose, the port valve sometimes remains open. When it does that, I can not take the hose off until I have drained the gun completely backwards through the hose and bleed valve. I have tried putting a drop of oil on the tip of it before I hook the hose up, and that works sometime. But I really think it needs replacing. Is this something I could do myself, or do I need to send this off somewhere for repair?

 

[Odoyle]

Hope that oil ain't petroleum based.

I'd whack it real fast and hard many times with a rubber mallet or the palm of your hand like you beating it to death if it refuses to shut its check valve automatically when bleeding.

 

[scallen2112]

Hope that oil ain't petroleum based.

I'd whack it real fast and hard many times with a rubber mallet or the palm of your hand like you beating it to death if it refuses to shut its check valve automatically when bleeding.

No, it's a silicon. I did try tapping on it, but am afraid of hitting it very hard. But I shouldn't have to, I don't think; which is why I am wondering if this fitting and valve can be changed at home, or if I need to send it off.

 

[Airgun-hobbyist]

The foster filler o-ring has gone bad from high pressure air rushing by it. I was told that they get "burnt" by the air and loose their seal if you fill fast. Replace the o-ring and you should be fine, and maybe fill the air in the gun a little slower. Periodically I will put a very small drop of silicone oil in the fill probe so it wets the o-ring as well. It has helped me from having the same issues as you were the fill probe won't seal after a fill.

 

[Loren]

I have had that happen to a couple of mine. I ended up just replacing the valve with a better quality valve. The OEM part is really not the best.

 

[scallen2112]

The foster filler o-ring has gone bad from high pressure air rushing by it. I was told that they get "burnt" by the air and loose their seal if you fill fast. Replace the o-ring and you should be fine, and maybe fill the air in the gun a little slower. Periodically I will put a very small drop of silicone oil in the fill probe so it wets the o-ring as well. It has helped me from having the same issues as you were the fill probe won't seal after a fill.

I'm not following you. What O-ring are you speaking of? The Texan just has a male foster fitting with a check valve inside it. It is that check valve that is sticking open.

 

[scallen2112]

I have had that happen to a couple of mine. I ended up just replacing the valve with a better quality valve. The OEM part is really not the best.

Thanks. Where did you get the valve? I couldn't find it as an AirForce part. If there any particular procedure to replace it? I will admit to being a little leery of working on a part that holds in that much pressure.

 

[Loren]

There is an O-ring as part of the check valve.

 

[Loren]

https://www.bestfittings.co.uk/shop/fill-probes-adaptors/high-pressure-fill-valves-caps/best-fittings-stainless-steel-high-pressure-fill-valve/

or 

https://www.amazon.com/gp/product/B07HKXV157/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1



It unscrews from the larger valve body with the gage...etc. Use Teflon tape when installing the new one.

 

[scallen2112]

Well, that was nice. Airforce is replacing the part and sending it to me. All the way down to the Teflon tape on the threads of the fill port.

 

[scallen2112]

There is an O-ring as part of the check valve.

Ah, ok. I see it now on the schematic from the Amazon page. Thank you, Loren. I think I will grab an extra or two in case I have the same problem in the future.