Help on o-ring replacement/ leak between air tank and valve

Inspect the check valve.

I am new to the PCP game. Whereabouts is the check valve? 

I assume it is inside the valve itself? How do I pull that apart?

what other FX rifle is this rifle based on

https://fxairguns.com/support/

It is closet to the Typhoon. 

This is the schematic: https://spares.bagnallandkirkwood.co.uk/wp-content/uploads/2017/07/Type-F-Exploded-Parts-List-and-Diagram.pdf

I am thinking maybe y'all are talking about parts 15-22? 

Posted by: @version3-6

It is closet to the Typhoon. 

This is the schematic: https://spares.bagnallandkirkwood.co.uk/wp-content/uploads/2017/07/Type-F-Exploded-Parts-List-and-Diagram.pdf

I am thinking maybe y'all are talking about parts 15-22? 

Number 27 in the schematic.

Okey dokey. Got that apart and it seems intact to my totally untrained eye. 

@version3-6

There should be an o ring on a small stem that goes in to that part.

Look as the schematic again. 

The red thing in the picture in the center of the part you are holding.

Got that apart. It does look like the o-ring on the stem is old and dried out

So, I am going to replace it and put the valve back together. That should (hopefully) fix my issue with pumping. Still not sure what to do about the main valve leaking at the junction around the air reservoir

May as well put new orings throughout the gun.  If one is old and tired the others are too.

Bob in WV

   The small, tan 0-ring may be causing the leak You can try a light lube with silicon grease or moly to restore it until you get the seal kit. Such a leak can make hand pumping difficult. 

I swapped out the ring on the main valve and it seems to be holding air. The old one broke and crumbled when I pulled it off. Didn't get much above 150 bar, but when I put soap and water around that seal it wasn't blowing bubbles and it fired when I reassembled it.

I tried a swap with another o ring on the check valve, but the only one that allows any air at all is the original. Put some light grease on stem but it doesn't seem to help.

Needless to say pumping is still a nightmare. Maybe I just have a bad pump? Although when the check valve had the new ring the gauge on the pump went up nice and easy (that was probably just the tubing itself getting pressurized).

being a non owner of a PCP gun but many co2 guns, when a O-ring goes bad they should all be changed as Bob in WV stated 

the why is it is the right thing to do and you know your all set for X amount of years 

but the problem is most PCP rifle have so many O-rings of different sizes and hardness  

you buy an over priced kit or go to, say The O-ring Store and buy 10 of each and have a supply for a long time 

a crumbly O-ring i find a bit odd for a young rifle 

so if it is shooting that is good but i would look to find a supply of O-ring and things for the next time, you look more then capable to repair what is needed 

oh by the way what brand hand pump are you using 

https://www.theoringstore.com/

they have great service and selection 

take care 

mike

Not sure on the rifles age, actually. I know I am at least the second owner and all of the stamps on the reservoir and block etc say 2013 so I assume it is at least 7 years old or so. Would climate affect o-ring longevity? It came to me from Arizona so maybe it was just a drier atmosphere?

The pump is a Jufeng - it is a cheap one I got from Amazon. I would love to do a scuba setup but I doubt I  that could get that together for the $100 the pump cost me. 

i understand a budget but if you keep struggling with that pump you will lose interest in pumping the rifle up

this is the best pump for years 

https://www.airgundepot.com/hill-pump-mk4.html

shop around 

also think about just having to top it up but it can't be leaking 

PCP rifle are not cheap but once setup that can be 

What kind of effort is normally required for pumping? 

For me it is something like 300+ up and down and I am dripping with sweat after I am done. Still haven't been able to get it above 200 bar. Obviously once I get the O-rings replaced it should improve it a bit (I just talked to a technician at FX and he says they are supposed to be heading back to work on Monday) but since this is my first PCP I have no previous experience for comparison. 

What kind of valves do you need to get a carbon fiber SCBA tank setup? Those can be had for relatively cheap on eBay and the like. 

I am a skinny guy (5’11” 145lbs) in good health and I hand pump all my PCPs.  Nothing over 3000psi / 220 bar though.  Never more than 50 - 60 strokes per session though to avoid cooking the innermost O-ring.  I alternate between 2 pumps to give the previous one time to cool for at least 15min but usually 30 min.  

I have been in touch with FX and they should be sending me some new bits and pieces. 

I know we are just beginning to try to get back to normal from the virus but shipping is taking AAGGGGES. I suspect they have quite the back-log from the stay-at-home order. 

So, I gotta moth-ball it for now. I will update once I have the new parts in and have done some testing etc. 

Ok, got my parts and swapped out the pump. I was able to get to 200 bar with 135 up/ downs in 5 minutes. Still a bit of work, but nowhere NEAR what I was doing before getting the better pump. 

Now my problem is that it won't hold air. I had it to 200+ yesterday and now I am less than 100 24 hours later. Got all of the rings on the valve and tank swapped. Maybe the stem on the inlet valve should be replaced? 

I was able to get some accuracy testing done. First target was an off-hand and the second was prone with an arm cuff + sling. Inner ring is 1" and those are three-shot groups. I need to dial my sights in a bit more and working on staging my trigger - haven't found the weight-of-pull I want yet.