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EVOL Help with a leak

Nealgl1985

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When I went to use my evol mini .22 the other day I found it was empty. It appears air is coming from the barrel. It would not air up at 1st when I hooked it to the fill tank so with the gun cocked and probe in the open position I covered the barrel with my finger and it sealed up enough to hold air.

I put a drop of silicone oil in the foster fitting and filled her up. She leaked back down to 0 overnight.

I've ordered the orings, Ultimox 226, and barrel wrench. Is there anything else I will need other than some allen wrenches and normal tools?

Has anyone else had this problem and what oring did you replace to fix it?

Thanks
 
Last edited:
I'll post here and on AGN

Are you 100% sure the leak is from the barrel? When filling these guns from empty I've always had to put my finger over barrel to seal. Also no need to cock the hammer as they have a floating hammer so no pressure on valve stem. I havent heard of a valve sealing issue yet but anything is possible I suppose. I'd venture to say it's not that though.

Anyways It's very simple. First I degas but in your case you don't need to. But loosen the burst disk until you hear air leaking and then leave it be. Depending on time when yours was made its either on the side exposed or hidden under the chassis. Mines older and exposed. If its under the chassis you obviously cant do it until the chassis is off. Once you remove the barrel, which they are on there tight so don't be afraid to hit the wrench with your palm or rubber hammer or something. You won't break anything on the gun. Anyways remove the barrel then you need to remove these 2 screws. The large one holding the chassis to the block, and the front one holding the rail to the fill/gauge block.

20231002_075823.jpg20231002_075832.jpg

Then remove the safety bolt. Then simply remove chassis from the action. After that unscrew the airtube from action and fill block also. You then need to push the reg out. A wood dowel or piece of PVC pipe is what i use. I push from the regulated side so not bump the adjustment screw on the other end. There will be 3 orings here, 2 on reg and one on fill block. Reg has one -117 and one -122 oring. The fill block -122. I wouldn't mess with the orings internally on the reg, haven't heard of any issues there but never know. Also at this time I would do the foster fitting orings and under the gauge on the fill block. The foster fitting leak is I think the most common on these guns.


After this clean your threads good, lube with ultimox and the orings and screw it together. Make sure you put the reg into the breech block first and then screw the tube on to it. After that just make sure you lineup the front block to the rail for the bolt to go it before putting air in.

This video helps alot also! I'd recommend watching it.

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Going to do a soapy water spray down and see if I can find the leak. I only assumed it was coming from the barrel because it sealed when I covered it with my finger.
 
Like @Dairyboy stated, it is not likely the valve. It COULD be, but the valve is likely just open because it lost its pressure from a leak elsewhere. In my experience, the front guage/foster fill block seals are the culprit. My advice, replace every seal there first. To add to dairyboys breakdown, don't forget to unscrew the safety knob before trying to remove the chassis. If the gun still leaks, replace the two main seals on the reg, the reg guage seals and possibly the burst disc. That is essentially every o ring that needs replacing, aside from the internals of the reg and valve which Ive never heard of issues with. DO NOT cross thread that front block on reassembly.

To add to your tools, I would pick up a gauge socket from aoa as well, to make it easy to remove the front gauge.
 
Like @Dairyboy stated, it is not likely the valve. It COULD be, but the valve is likely just open because it lost its pressure from a leak elsewhere. In my experience, the front guage/foster fill block seals are the culprit. My advice, replace every seal there first. To add to dairyboys breakdown, don't forget to unscrew the safety knob before trying to remove the chassis. If the gun still leaks, replace the two main seals on the reg, the reg guage seals and possibly the burst disc. That is essentially every o ring that needs replacing, aside from the internals of the reg and valve which Ive never heard of issues with. DO NOT cross thread that front block on reassembly.

To add to your tools, I would pick up a gauge socket from aoa as well, to make it easy to remove the front gauge.
Will I need the shroud removal tool do you know?
 
Like @Dairyboy stated, it is not likely the valve. It COULD be, but the valve is likely just open because it lost its pressure from a leak elsewhere. In my experience, the front guage/foster fill block seals are the culprit. My advice, replace every seal there first. To add to dairyboys breakdown, don't forget to unscrew the safety knob before trying to remove the chassis. If the gun still leaks, replace the two main seals on the reg, the reg guage seals and possibly the burst disc. That is essentially every o ring that needs replacing, aside from the internals of the reg and valve which Ive never heard of issues with. DO NOT cross thread that front block on reassembly.

To add to your tools, I would pick up a gauge socket from aoa as well, to make it easy to remove the front gauge.
Good catch on the safety removal. Forgot about that. I'll edit and add in for others just for future reference
 
I’m going through this right now too. In 3 days I lost 1000psi. Slow leak, but still a leak. I ordered all the orings from the thread here, and I couldn’t wait and just tore down the gun. Almost completely apart in less than 5mins!! Eat your heart out FX boys!!!

Anyway, I didn’t notice any damage to any of my orings, so I’m hoping one just got hard or deformed or something. I wouldn’t replace one and then air it up. You have it apart, so just do a full reseal. It’s a maintenance thing anyway. No reason to replace only one or two.
 
I’m going through this right now too. In 3 days I lost 1000psi. Slow leak, but still a leak. I ordered all the orings from the thread here, and I couldn’t wait and just tore down the gun. Almost completely apart in less than 5mins!! Eat your heart out FX boys!!!

Anyway, I didn’t notice any damage to any of my orings, so I’m hoping one just got hard or deformed or something. I wouldn’t replace one and then air it up. You have it apart, so just do a full reseal. It’s a maintenance thing anyway. No reason to replace only one or two.
I would check the orings under the foster and the gauge to be sure. My foster was really slow at first until it started letting loose. I didn't shoot for a month and noticed it was around 1k psi where I usually don't shoot it below 2kpsi.
 
I would check the orings under the foster and the gauge to be sure. My foster was really slow at first until it started letting loose. I didn't shoot for a month and noticed it was around 1k psi where I usually don't shoot it below 2kpsi.
I did soap it before I took it apart, and didn’t see any bubbles, but at this point, I’ll completely reseal it anyway. Then I’ll know if it still leaks, I’m not taking it apart for just 1 oring.
 
Typically you will find a leaking foster fitting. Not sure why, but this seems to be a standard problem.

The good thing is these rifles are EXTREMELY easy to break down. Just be careful and go slow so you don't cross thread anything.
 
I have all 3 of the tools and they are nice. It is nice to have them and not have to jerry rig something to work. They are fairly cheap when you consider how much the parts are id you need to replace them.
 
I was just informed that the barrel wrenches are no longer being made? Is this true @American Air Arms ?

I ordered from airgun sport since AoA was out of stock and just received a email saying they refunded me since these are no longer being made.

How do you get the barrel off if you don't have the special barrel wrench?

I guess 1 downside to the platform is you need special tools, that aren't readily available for purchase, to work on the guns. Or am I missing something and they are available somewhere else?
 
I was just informed that the barrel wrenches are no longer being made? Is this true @American Air Arms ?

I ordered from airgun sport since AoA was out of stock and just received a email saying they refunded me since these are no longer being made.

How do you get the barrel off if you don't have the special barrel wrench?

I guess 1 downside to the platform is you need special tools, that aren't readily available for purchase, to work on the guns. Or am I missing something and they are available somewhere else?
I haven’t heard anything about them being discontinued. You need them for all evol barrels, so I don’t see Tom doing that.
AOA is the major distributor for AAA so I would call them and ask.
They might take a while getting back to you this week being EBR though.
 
Where are you located? Message me and if close I can let you borrow mine. Yes the tools are expensive, but they are nice to have when you need them.
I'm not even worried about the $150 for the tools. I am in Michigan which is not close to you it appears.

As soon as Kevin @CTAirgunner heard I had a leak he offered to ship me his barrel wrench. I figured I better buy the tools I need, but no barrel wrenches appear to be available. The gauge socket and mod end cap removal tool is available though.
 
I'm not even worried about the $150 for the tools. I am in Michigan which is not close to you it appears.

As soon as Kevin @CTAirgunner heard I had a leak he offered to ship me his barrel wrench. I figured I better buy the tools I need, but no barrel wrenches appear to be available. The gauge socket and mod end cap removal tool is available though.
Mine can be on the way as soon as tomorrow if you need them bud
 

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