FX FX Maverick Compact help, please!

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YamahaR1

Member
May 3, 2017
295
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Bemidji, Minnesota
As the title says I need help and greatly appreciate any advice!
So I have a Maverick in the compact set up in .25 cal. The gun is well taken care of and has some bolt on mods and the internals are all stock except for the slug probe. Recently got a brand new 2nd stage regulator from FX with all o-rings installed and has a brass piston. Only O ring I needed to install was the one that’s about half way down just below the threads.
I had to replace original 2nd stage regulator because it was creeping and the atmosphere hole was having air leaking out of it. Now that it’s replaced regulator works great, refreshes quickly and holds at what it’s set too.
When I replaced old reg with new one I cleaned inside of the chamber out really well with a q-tip and then blew it out with compressed air as I didn’t want to clean with any type of solvent. Then I put the O-ring in that’s just below the threads dry, once it was in I put a light coat of silicone grease, also greased up the O-rings on reg before installing it. Thought everything was good to go and tuned gun and was off shooting. After a day I noticed the pressure gauge was lower than when I put it up. I inspected gun carefully and rechecked everything thing for air leaks. Found that the atmosphere hole right by trigger was leaking again. Drained the gun and pulled reg out inspected all O-rings with a magnifier closer and no noticeable issues or damage to O-rings. Re-greased and installed once more, same results as before very slow leak.
Pulled tank off and let gun sit for a couple days, put tank on and when gun was filling up with air I could actually feel the air leaking out of the same spot as before. But was leaking a great deal more cause I could feel it and hear it. Pulled tank off let all air out and then put tank on again, but this time gun held air but was still leaking slowly like before. Anyways any help would be greatly appreciated cause I’m at a loss with what’s going on.

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You are going to have to inspect the grooves and surface that both sides of the oring in question rides on. You inspected the oring with magnification, and that’s what I would do also. But now it’s time to look for a scratch on the hard surfaces. That’s all it takes when dealing with these kinds of pressures. A design flaw or a careless assembly person with a sharp object and its game over. I’ve used my bore scope for these operations almost as much as I’ve used it for looking at my leade, crown or rifling.
 
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The bottom o-ring on the adjustor is the issue and possibly the little PIA on the inside of the housing. As an FYI those two on the adjustor are suppose to be N90's but the online drawing says N70, I got a rebuild kit with them specified N90 from FX. Todays pro-tip, there is almost no way in H to get them on without putting them in boiling water to soften them a touch, or else buy 50 of them from The o-ring Store, because they will break. I'd still stock up on all of the usual suspects, it's a cheap investment. Somewhere on the forum I've listed all of the regulator o-rings and the correct numbers/ hardness.
 
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No it’s not the adjustment o rings. Or the regulator body o rings. It would be the one that’s actually inside the gun. That has the damage around it even though there is a new o ring that I put in there. I’m guessing that’s where the leak is coming from. Appears the aluminum has some scaring.
O ring number 18 is the one with scaring around it.

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YamahaR1 said:
Hogkiller the o rings you specified that needed to be N90’s are all as they should be. Least that’s what was stated on the packages when I received them from FX and all but number 18 were already installed. So that saved me the hassle of heating them up to put on.
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Good, N70's will work but...and I'm guessing here, they found they would leak. I had the same issue, leaking out of the atmosphere port, I was told it was the bottom o-ring, even a micro-scratch can leak. #18 is fun to replace, be sure to use brass picks, you can use a needle to get the old one out. I'd just replace all of them, it's easier than messing around one at a time. They're cheap from The O-ring Store. If the block is messed up, FX will send you a new one, it's not as daunting as it appears to be, hardest thing is to replace the valve seat, it does pop out with a pick and a dowel to push it back in.
 
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You could also try either a thicker o ring in that tunnel like instead of the 10 x1.5 a 10 x 1.7 or replace it with a polyurethane in a 10 x 1.5, DURO 90.

Another area of leak is the tiny 11 x 1(if I remember) o ring that’s under the male QD. I worked on a wildcat MK3 BT that had leaks in both that reg tunnel and the male QD. I removed that o ring from under the QD and used a Dowty seal and it sealed right up. On the reg tunnel it took three tries each with a new 10 x 1.5 and it finally sealed up
 
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Bravo1956 said:
Really love FX airguns but this is one of the things that can be very frustrating about them, all the orings and troubleshooting the issues, and the fragile regulators.
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I don't consider the regulators to be 'fragile' unless you do something really stupid and smack them with a sledge hammer.
YamahaR1 said:
So the bottom Oring on the piston is what cause the leak out of the atmosphere hole?
Talked to FX they said the bottom one comes with a NBR70. So I should get a NBR90 instead and see if that fixes the issue

I will try a slightly larger o ring and see if that helps as well.
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No need for a 'larger' one just buy a bunch of all of them and start replacing. o-rings have tolerances, if you happen to get some that are on the extreme of the tolerance, i.e. cross section towards the minus bottom, they may not seal as well as those towards the thicker size, also if the machining is on the plus side of the tolerance you may be on the edge of it leaking. I have a vendor that lets you select the tolerance range. Only issue is.....can't find it in my list so it's not going to do you a lick of good right now. I use both McMaster-Carr and The O-ring Store. The service out of The O-ring Store is beyond excellent, they almost come and deliver and install it.
 
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Bravo1956 said:
Maybe fragile not a good word, but not very robust compared to other regulators I feel.
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They are fine, actually the same design as Huma, both use Belleville's. It's very easy to mess up the o-rings if you're not patient and use the right tools. Honestly, I'm not a fan of silicon oil, I prefer something slippery like Mobile 1. I also like to match up the Bellevilles, keep them all the same size, evens out the stress, a light polish on the contact points.
 
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YamahaR1 said:
Sorry for long delay was out of country, I did not fix the leak. Got a new regulator from fx and have replaced o-rings with no fix. Checked inside of regulator chamber and doesn’t appear there is any cracks in aluminum. I’ve gotten so frustrated with it, it’s just sitting now.
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Yeah, it's frustrating, so please indulge me/us, you've put a balloon on the barrel to see if it's leaking there? You've put some soapy water or silicon on the breather hole to see if it's leaking there? Is #1 reg. rebuilt? On my band new Mav. VP they'd messed up an o-ring at the factory on my #1.
 
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@YamahaR1 to let you know mine held for now i installed a huma reg which i am not happy with cause the fact that to degas the gun have to dry fire all the way. But for now it held so i believe there was minor scratches on the piston rod due to the fact that i had to manipulate with metal tweezers or/or both the outer housing of the reg it self i am pretty sure ,so to answer to your new reg install and did not fix your problem what i will tell you is pull out gently clean inside the plenum and change again the o ring that sits below the threads polish the Belleville waschers and lube them before install it inside because if edge of the waschers is a bit rough will scar the o ring . I have new piston rod on the way with some o rings and the rod pull up tool i hope will fix yours to. Happy festive to all.
 
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sniper maverick said:
@YamahaR1 to let you know mine held for now i installed a huma reg which i am not happy with cause the fact that to degas the gun have to dry fire all the way. But for now it held so i believe there was minor scratches on the piston rod due to the fact that i had to manipulate with metal tweezers or/or both the outer housing of the reg it self i am pretty sure ,so to answer to your new reg install and did not fix your problem what i will tell you is pull out gently clean inside the plenum and change again the o ring that sits below the threads polish the Belleville waschers and lube them before install it inside because if edge of the waschers is a bit rough will scar the o ring . I have new piston rod on the way with some o rings and the rod pull up tool i hope will fix yours to. Happy festive to all.
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I use spray contract cleaner, blast it upside down and give it a good hosing out, it won't hurt the aluminum or the anodizing and it evaporates quickly. Then a touch of compressed air. And I still dislike silicon oil.
 
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