Falcon FN19 fill help needed

I picked up a nice Falcon FN19 at the last Midwest Airgun show, and in my excitement I forgot to ask for the fill probe. I ordered one from Best Fittings in the UK and it arrived today. When I got the rifle it was holding air, I took a few test shots and it is currently still holding. However, I went to top it off and it won't take any air. When I insert the probe and start filling, my compressor hits about 450psi and stops rising. Has anyone encountered a similar issue and if so, what was the solution.
IMG_7372.jpeg
IMG_7374.jpeg
IMG_7375.jpeg
 
Last edited:
I had a similar issue with my Falcon. Whenever I relied on hand pumping the gun, I remember having to change the o-rings frequently which are located inside the quick fill adapter (instead of on the fill probe). However, sometimes I just had to tighten the threaded rings which hold the o-rings in place and/or add silicone grease to the fill probe.

It was much more reliable filling from a tank when I could more rapidly pressurize the fill assembly.
 
  • Like
Reactions: baranjhn
I had a similar issue with my Falcon. Whenever I relied on hand pumping the gun, I remember having to change the o-rings frequently which are located inside the quick fill adapter (instead of on the fill probe). However, sometimes I just had to tighten the threaded rings which hold the o-rings in place and/or add silicone grease to the fill probe.

It was much more reliable filling from a tank when I could more rapidly pressurize the fill assembly.
same... the Quick fill moderator can be finicky for sure.
Those old Falcons are great looking guns. Congrats
 
  • Like
Reactions: baranjhn
Sounds like there's a leak between your fill probe and the inlet valve itself; why your compressor won't go beyond 450 PSI. Since the inlet valve is feeling only 450 PSI, it won't open because there's more pressure than that in the chamber-tube holding it shut. I think there are seals in the fill-probe orifice; that must be the culprit.
 
... However, sometimes I just had to tighten the threaded rings which hold the o-rings in place and/or add silicone grease to the fill probe...
I tightened up the fill adapter(?), where the price slides in and liberally applied silicone grease to the probe.... no dice.
Sounds like there's a leak between your fill probe and the inlet valve itself; why your compressor won't go beyond 450 PSI. Since the inlet valve is feeling only 450 PSI, it won't open because there's more pressure than that in the chamber-tube holding it shut. I think there are seals in the fill-probe orifice; that must be the culprit.
Then I took the fill adapter off, put a few drops of silicone oil on the o-ring on the back side of it, and placed several drops into the air cylinder opening. I'm letting it sit upright for an hour or two to see if that helps.


tempImageZpGYkg.jpg
tempImageWCEyw3.jpg
tempImageFmFdy4.jpg
 
Last edited:
You can try a little soapy water around the fill port while filling, if it bubbles, air is escaping.
I tried that and I couldn't detect a leak. I went and ordered a new quick fill set up from Best Fittings in the UK. I'll have to get a moderator adapter now since I won't be able to use the original mod.