FX FX Wildcat MK3 leak (cannot be filled anymore)

For air to pass the valve and exit the barrel it is impossible to have a proper seal. UNLESS there is a fracture in the gun body. Air is passing the valve. Somehow. Whether it be the face of the seat has tiny imperfections. Micro fractures, the Delrin gasket on the valve may be imperfect. Air is passing the valve
The Delrin gasket on the valve pin you mean?
 
It’s probably safe to assume your valve is the issue. Replace it. Just the oring wasn’t the issue. Once again the valve can “look” good the imperfections aren’t visually perceptible sometimes. The check valve on the fill port sounds shot now too. Like the check valve was installed wrong or it’s screwed.
Talking about imperfections just have a look at a brand new valve:



I wouldn't call this perfect... would you?
The thing is that you can buy from FX a valve pin or a valve seat separately.
If FX was serious, these two parts should have been offered as a pair only.
They should have been machined together and then matted at the lathe one against each other
with a smoothing compound to a mirror finish. Its a metal to metal seal.
No wonder these leak all the time.
 
The Delrin gasket on the valve pin you mean?
technically the pin and seat are the valve together. But yes.


as for the picture, Its not metal to metal, The face ring is all that has to be good and typically the side with the wider flared Outer diameter is the valve seat face the Delrin gasket rests against. "usually" doesn't matter though, If that's how the wildcat does it, that's how it is. The Inside and outside look like less than stellar machining, but the face doesn't look too bad. I'd be looking for divots,chips or rises in the delrin ring around the metal conical part of the valve pin. it helps if the two surfaces are perfectly flat, only one surface on the seat needs to be machined with the highest possible tolerances.
 
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valve wc.png
 
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If these are the two surfaces that mate together in order to seal, then if you have a look at the video below,
they do not. The Delrin part goes inside the seat cone and does not touch the outer top flat surface of the
seat cone. The seat looks perfectly flat. The Delrin has some damage at the opposite side of the seat but
the other side is fine. If these are the two mating surfaces, then a whole chunk of the outer diameter of
the Delrin part is missing... :) Are you sure these are the two mating surfaces?

 
Somewhere air is passing through without the hammer resting against the valve pin. There is one passage way for Air to reach the barrel. If there isn’t some issue with the valve it can only be the aluminum billet having structural damage. I noticed a tiny ding on the cone on the pin. The far side of the derlin seal shouldn’t matter. I don’t know what to tell you. You’ve got good macro footage. If you notice nothing on the shoulder of the delrin seal on the valve seat side i am at a loss. Is there an alignment issue? Is the valve return spring present and correct. Are you sure all the parts are present? As for the fill port blowback. I don’t know man. Something is definitely wrong

Where is your regulator set?

did you use an fx oring or just try to match the size
 
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Somewhere air is passing through without the hammer resting against the valve pin. There is one passage way for Air to reach the barrel. If there isn’t some issue with the valve it can only be the aluminum billet having structural damage. I noticed a tiny ding on the cone on the pin. The far side of the derlin seal shouldn’t matter. I don’t know what to tell you. You’ve got good macro footage. If you notice nothing on the shoulder of the delrin seal on the valve seat side i am at a loss. Is there an alignment issue? Is the valve return spring present and correct. Are you sure all the parts are present? As for the fill port blowback. I don’t know man. Something is definitely wrong

Where is your regulator set?

did you use an fx oring or just try to match the size

All o-rings were from the FX reseal kit.
All parts are installed, nothing is missing.
The thing is that if we do not know how exactly the seal works,
we will not be able to see if there is a problem there or somewhere else.

I am trying now to find spare parts, valve pin and seat.
My AEA HP SS is starting to look nice now...
 
All o-rings were from the FX reseal kit.
All parts are installed, nothing is missing.
The thing is that if we do not know how exactly the seal works,
we will not be able to see if there is a problem there or somewhere else.

I am trying now to find spare parts, valve pin and seat.
My AEA HP SS is starting to look nice now...
A valve seal is a valve seal. Delrin buts up against the seat, forms a seal. My mistake. I’ve not had an fx gun for a while and forgot the inside arrangement. most of my guns have a tiny chamfered shoulder and a more cylindrical valve body. The Delrin interfaces with the metal of the seat. Usually the shoulder of the front face and the chamfer. If you can Align the pin centrally in the seat and apply pressure on the pin and see light you have an issue. If you can see any divot, dents, flattening. Or shaping other than the original form. There is an issue. Air is passing the valve.
 
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If it were me I’d buy a new complete valve pin and new complete valve seat. As far as the gauge reading zero try loosening it just a touch. I bet it is over tight and not reading.
I have ordered a new set. Hopefully I will have them tomorrow.
The thing is, that I still do not understand how the valve poppet seals the valve seat.
 
it is the delrin being compressed against the metal of the seat by the valve spring + Air pressure.

To test the theory, I resurfaced the Delrin edge with a slight taper and a rounded edge from 1000 grit to 5000 grit.



I also polished the valve seat with polishing compound.



I will reassemble the airgun (for the 100th time... :) ) and see what happens.
 
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To test the theory, I resurfaced the Delrin edge with a slight taper and a rounded edge from 1000 grit to 5000 grit.



I also polished the valve seat with polishing compound.



I will reassemble the airgun (for the 100th time... :) ) and see what happens.
the seat looks very good. the delrin might be a pain, but i hope it works. It's a brutal process to disassemble, reassemble, fill and fail over and over.. But, you'll get to intimately know your gun and feel much more satisfied when it finally all works. best of luck my Hellenic friend.
 
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the seat looks very good. the delrin might be a pain, but i hope it works. It's a brutal process to disassemble, reassemble, fill and fail over and over.. But, you'll get to intimately know your gun and feel much more satisfied when it finally all works. best of luck my Hellenic friend.
My friend thank you for the encouragement but I failed... Same thing, air is rushing out the barrel like there is no seal at all.
At least I tried.

I am buying tomorrow the spare parts and will try again.
Wildcat from hell...