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PostPosted: Fri Mar 18, 2016 4:35 pm 
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Recently landed a used and somewhat beaten up 2240 with a shoulder stock for a price I couldn't pass. As some of you know I had requested stock grips for it and had no shortage of generous offers from several of the members here. But before I go into restoring the thing I wanted to run a quick test to ensure it works. That didn't go very well.

Added CO2 to it along with a generous amount of Pellgun oil, cocked and upon depressing the trigger I could hear the gas escaping very fast from around the middle portion of the gun. There was no gas escaping from the cap, so it makes me think it's where the CO2 makes contact with the gun or a seal somewhere. I know very little about these so I'm here hoping for some input on what is needed to get it work like a pro.

Also noticed the safety moves freely on its own. Looks like an O'ring is missing (see pic). If that's the case does anyone know the size?

Still haven't gotten the stock grips for the gun along with the rear blade as I was hoping someone locally has them as spares. If not I'll be bothering Edmonton500 since he was the first to offer. Maybe you have the seal I'm missing too? If so and no one locally has these, I'd like to buy them off you at the same time, since you'd have to mail these to me (or someone else that may have the missing parts). Would much rather buy what's needed from someone that may be shipping me the grips instead of paying a $25 shipping fee for a seal that may cost a couple of bucks from a dealer.

Pity, was hoping to finally see a 2240 in action. But seems like easy enough a fix. If needed I can open the gun to look, but before doing that wanted to first run past you folks as guidance will be needed.

Once I get it working the next step will be to see what can be done to the worn out paint. Seems like a fun project.


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PostPosted: Fri Mar 18, 2016 4:47 pm 
Almost sounds like the transfer port seal is leaking.

You need a .50 hex key to take the breech screw out. Just forward of the bolt. Take the barrel band off and then that screw and you will notice the transfer port. There would be a seal in between the transfer port and main tube.

Seal kits for these guns are 13-18$

Also the cross bolt safety there is not a o ring, but a small detent ball and spring. If you take the grip off you will notice a spring and should be a detent ball that once assembled the spring pushes the detent down on the cross bolt. Don't tip it upside down.

Chances are the small detend ball is missing or the spring is too weak. But you can also push too much and push the safety too far.

By the looks its well worn and a re seal might be a good idea.


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PostPosted: Fri Mar 18, 2016 6:30 pm 
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If it held co2 before you fired it, then it is the valve seal, or caplet seal, if it lost all its co2 after pulling the trigger. A valve stem seal or caplet seal are the only seals that holds the co2 After piercing the cartridge. there is no transfer port seal in a 2240. There may be an o ring on the TP, but it's not a seal. You should strip it down anyway, and get familiar with how everything works and how it goes together. Consult an online schematic to make sure you have all the parts.

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PostPosted: Fri Mar 18, 2016 7:05 pm 
joe hickey wrote:
If it held co2 before you fired it, then it is the valve seal, or caplet seal, if it lost all its co2 after pulling the trigger. A valve stem seal or caplet seal are the only seals that holds the co2 After piercing the cartridge. there is no transfer port seal in a 2240. There may be an o ring on the TP, but it's not a seal. You should strip it down anyway, and get familiar with how everything works and how it goes together. Consult an online schematic to make sure you have all the parts.


Sorry tube to breech seal.

Image


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PostPosted: Fri Mar 18, 2016 7:20 pm 
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Yes, there is a square-section rubber ring under the stock steel transfer port part, but all that does is prevent wasted CO2 upon firing, helping keep as much CO2 as possible moving towards the pellet. Dumping a CO2 cartridge would relate to leaks at either the caplet /valve junction (the beige rubber seal shown in your illustration) or at the valve poppet. Both are possible. Both would cause a gas dump once the cartridge is pierced. Either one could cause the dump alone. You will have to pull the gun apart and check the front gasket (beige seal) first, then if that seems intact open up the valve and examine the poppet seal for any imperfections.

As for the safety, there is no O-ring there. A tiny ball bearing on the end of a tiny spring, that's all. Easy to lose. I disable the safeties on mine as I don't trust safeties. The only safety I trust is in my head.


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PostPosted: Fri Mar 18, 2016 7:23 pm 
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i hate to break it to ya amigo but the gun is fubar'ed and non-repairable plus i heard a gypsy cursed it so you should give it to me... i would pay for the shipping ofcourse 8)

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PostPosted: Fri Mar 18, 2016 7:26 pm 
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Correct, it lost all of the CO2 upon it being pierced. Guess this means it would be the two bottom gaskets in the pic that Robert posted?
I was in the process of gathering tools for the teardown, lots of vids on youtube and it seems like a snap compared to tearing down the QB78. But don't have a very tiny allen key to remove the 3 bolts that hold the trigger plate in place. Don't suppose it's necessary to remove the plate anyway in order to access the valve huh?
Plan to still disassemble it tonight to look around and see what's needed. Thanks for the help.

Edit: just seen H2P's post before posting this. Let this be a warning to all out there: no one hacks things 2 pieces like him. DO NOT send this nuts gun surgeon your guns!

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PostPosted: Fri Mar 18, 2016 7:41 pm 
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While it is possible the leak is at the valve body O-ring, it seems unlikely as that one is under a lot of compression and completely contained within brass. If it's very old the rubber could be cracked, and if course then it'd leak. But much more likely the leak is at the beige sealnor the poppet. The poppet seal is not shown in the picture. It looks like these, closest to the middle one:
Image
Here's one which has failed:
Image
The seal material is very weak and prone to becoming irregular due to contaminants or just normal use. A Disco poppet is a drop-in replacement, or so I've heard. I make my own out of delrin and drill rod.


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PostPosted: Fri Mar 18, 2016 7:45 pm 
Joolz wrote:
Correct, it lost all of the CO2 upon it being pierced. Guess this means it would be the two bottom gaskets in the pic that Robert posted?
I was in the process of gathering tools for the teardown, lots of vids on youtube and it seems like a snap compared to tearing down the QB78. But don't have a very tiny allen key to remove the 3 bolts that hold the trigger plate in place. Don't suppose it's necessary to remove the plate anyway in order to access the valve huh?
Plan to still disassemble it tonight to look around and see what's needed. Thanks for the help.

Edit: just seen H2P's post before posting this. Let this be a warning to all out there: no one hacks things 2 pieces like him. DO NOT send this nuts gun surgeon your guns!


.50 Allen key is the main one you need for the breech screw. As for the plate that just exposes the trigger and sear. I only ever took that apart when I shimmed my trigger and installed a lighter spring and guide. When you remove the trigger mech if the spring is sitting up a bit the detent should be there but you can flip it up side down and cup your hand to collect.

Apparently you need a collet to take apart the valve to change the o ring.


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PostPosted: Fri Mar 18, 2016 7:53 pm 
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Thanks for the clarification, Gerard. Had started taking it apart when I realized the tiny breech screw (the one under the bolt) is similar to the trigger's plate - the very tiny allen key that I don't have. Guess I'll be hitting a couple of tool stores tomorrow in order to find this tiny allen key. Anyone knows what size it is? Would be a lot easier if I knew what to ask for (don't want to walk into a store with a gun in hand).

Looking through the barrel the valve steam seal appears to be in good shape, so it wouldn't surprise me if the culprit is the seal you describe above. Since these don't come in the kit I'll try to make my own, if I can locate a source for this delrin. While at it, is there a reliable way to make a valve stem seal, if I do end up needing one? Much rather make my own as I foresee a lot of use for this gun and prefer to have these handy in abundance.

Edit: Robert beat me to it. Is that .05"? Guess it couldn't be .05mm so I'm assuming it's the imperial one.

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PostPosted: Fri Mar 18, 2016 7:58 pm 
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Collet? I just put the valve in a vise with aluminum around the body to prevent scraping and to grip it better, then grasp the shorter front end with pliers and unscrew it. After the first time there'll be pliers marks but it doesn't hurt the valve. I just file down box end wrench flats on two sides of the part after the first time, for whatever wrench seems a decent match.

Making a good delrin seal takes a bit of trial and error. Some go for a conical type to seal closer to the stem, minimizing force required to open, but I haven't had great luck with that style. Mine tend to follow the whole shape of the seat, or at least most of it. Searching for 22** valve poppet seals and related terms will turn up lots of images on Google. A lathe is kind of necessary. Made one like this for my QB78 as well, as it has a Disco valve installed.


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PostPosted: Fri Mar 18, 2016 8:08 pm 
Joolz wrote:
Thanks for the clarification, Gerard. Had started taking it apart when I realized the tiny breech screw (the one under the bolt) is similar to the trigger's plate - the very tiny allen key that I don't have. Guess I'll be hitting a couple of tool stores tomorrow in order to find this tiny allen key. Anyone knows what size it is? Would be a lot easier if I knew what to ask for (don't want to walk into a store with a gun in hand).

Looking through the barrel the valve steam seal appears to be in good shape, so it wouldn't surprise me if the culprit is the seal you describe above. Since these don't come in the kit I'll try to make my own, if I can locate a source for this delrin. While at it, is there a reliable way to make a valve stem seal, if I do end up needing one? Much rather make my own as I foresee a lot of use for this gun and prefer to have these handy in abundance.

Edit: Robert beat me to it. Is that .05"? Guess it couldn't be .05mm so I'm assuming it's the imperial one.


.050" Breech
1/16" Trigger Plate
5/64" Grub Screw ( Band )

GerardSamija yeah these are like rings but with a cut in them so they can close up. That when you clamp is like a perfect size that don't gouge/mark the valve up. I saw them on GMA and thought they were cool.


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PostPosted: Fri Mar 18, 2016 8:36 pm 
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So the trigger plate screw differs from the breech huh? It looks like the breech would be a 1.27mm and the trigger a hair under 2mm. So great that Crosman had to use American measurements instead of something the rest of the world uses.
Yep, will try to secure these first thing tomorrow.

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PostPosted: Fri Mar 18, 2016 8:45 pm 
Joolz wrote:
So the trigger plate screw differs from the breech huh? It looks like the breech would be a 1.27mm and the trigger a hair under 2mm. So great that Crosman had to use American measurements instead of something the rest of the world uses.
Yep, will try to secure these first thing tomorrow.


Yup I bought a screw kit and came with all the keys I need. But should be able to find those at CT or other places.


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PostPosted: Fri Mar 18, 2016 8:53 pm 
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I seen some kits in metric that comes with 1.27mm and the next size up is 2mm. Any chance you or anyone else could try the 2mm on the trigger screw to see if it fits? I'd much prefer to buy a metric set.

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