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Jim Gillilan's Custom 1322 Carbine

Jim Gillilan's Custom 1322 Carbine w/Custom Stock

Here's one I'm especially proud of and is modded all over, doing 12fpe at 15 pumps.
Stock is Teak from Thailand and super light weight 1322 Carbine!

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Is this crazy or will it work??

April 29 2017 at 10:34 PM

ray1377  (Login ray1377)
Crosman Forum Member
from IP address 71.143.248.32

I have a slow leak on my benjamin discovery.
I've listened and don't hear any "hissing" or releasing of air.
I've taken it apart and replaced all the o-rings in the pressure tube.
The two on the front side of the valve, the two around the gauge block, and the one at the filler end.
I also replaced the little o-ring underneath the pressure gauge.
And it still has a slow leak.
I'm thinking one of two places.
Either the check valve in the foster fill fitting, or the exhaust valve?
I can't really check the exhaust valve short of replacing either it or the entire valve assembly.
But I did have a thought how to check the foster fitting.
Could I not take a kids party balloon and fix it around the filler port with a zip tip or something and then see if the balloon expands over a short period?
Would this not tell me if it got a slow leak there?
Thanks
Ray


    
This message has been edited by ray1377 from IP address 71.143.248.32 on Apr 29, 2017 10:36 PM


 
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Steve in NC
(Login pneuguy)
Crosman Forum Member
162.198.201.47

Yes -- to both. Yes it might work and yes it's (pretty) crazy.

April 29 2017, 10:40 PM 

The old standby of soapy water would probably work better. If you go the balloon route, why not also put one over the muzzle (with the bolt closed) to check the exhaust valve?

But in any case, don't forget that Crosman pressure gauges are a frequent source of leaks.

 
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ray1377
(Login ray1377)
Crosman Forum Member
71.143.248.32

Good idea Steve--

April 29 2017, 11:01 PM 

I'll give that a try and see what happens.
Thanks
Ray

 
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Bio
(Login Biohazardman)
Moderator
71.236.167.69

Re: Is this crazy or will it work??

April 30 2017, 4:03 AM 

Or you stuff the front of the gun in a bucket of water and watch to see where the bubbles come from it should not be difficult to figure out what is leaking then.
I used to have a life. But now I have the forum. I am a sick man?

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gubb33ps
(Login gubb33ps)
Crosman Forum Member
162.192.93.122

Likely more than you need...

April 30 2017, 9:05 AM 

They do make industrial/commercail leak detection stuff...and basically NONE of us has that laying around.

If you got little kids, may have some bubble making stuff (those little plastic bottles with the plastic ring to blow though from the Dollar store?).

If not, we pretty much all have water and some form of soap.

YEah...water freaks airgunners out. Not sure why, it's not as if a pressurized system is going to suck stuff in, and we manage the "art of drying" every time we take a shower.

I count 8 places you'd need to cheack for "static" leaking (leaking while it's just sitting there)but only 7 of them are easy to get to.

Basically everwhere there is a sealed opening or sealed joint to the outside world.

1. Leak from the muzzle (if the bolt is closed) is the valve stem seal not sealing.
2. Leak from the open end of the fill nipple is the little o-ring inside the fill nipple not sealing.
3. Can leak from the threads of the nipple into the end cap.
4. Can leak at the joint of the end cap and the air tube.
(the next 3 are right next to eachother, so will need to really look closely to tell which is leaking)

5. Can leak from the back of the gauge itself (there is a little hole on the back face of the gauge...if it bubbles out of that, you need a new gauge).
6. Can leak from the threaded shank of the gauge were is screws into the gauge block inside the tube.
7. Can leak from the opening in the tube that the gauge's shank passes through to get to the gauge block. That gauge block has an o-ring on each side of that hole that often go bad.

8 (The harder one). Could leak out the back end (striker end) if the o-rings that seal the valve to the tube or the o-ring that seal the two halves of the valve go bad. To check that, are going to have to take the rifle apart becasue we need to check around the rear of the valve/air tube.

USUALLY, will find that if the o-rings on the valve body leak, will find a little bubbling at the two valve retetion screws in the side of the air tube, the front trigger housing screw...but those may not show a slow leak (air taking the easiest passage out, which is along the sides of the valve to the back).

So, out the stock...barrel band off...reciever and barrel off...pluck out the transfer port parts so you don't lose them...rear end cap, striker and striker spring out...now you can look down into the rear of the tube and see the back of valve. It's still retained by all the fixation screws, so you can gas it up for a leak check aound the rear end of the valve.


THE TRAP:

Stopping at the first leak you find?

What we (myself included) often do is detect a leak, fix it, and then get POed that the thing still leaks.

Well..there is no rule saying that there has to be just one leak, but we (myself included) stop checking once we find the first one (especially it is one of the simple ones to fix).

We might even have been right and there was only one leak...but we created a new leak while fixing the first one.


    
This message has been edited by gubb33ps from IP address 162.192.93.122 on Apr 30, 2017 9:08 AM


 
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ray1377
(Login ray1377)
Crosman Forum Member
71.143.248.32

Ain't too keen on

April 30 2017, 8:07 PM 

getting an airgun or any gun for that matter wet, let alone dunking it under water.
But that would be one sure fire way to find a leak.
Thanks
Ray

 
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gubb33ps
(Login gubb33ps)
Crosman Forum Member
162.192.93.122

Just to show...

May 1 2017, 6:25 PM 

...not a Crosman in this case, a BAM 51, but it pretty well localized the leak. (yep...dowdy seals can go bad).

Under 2.5" of hot water.

photo 473d4248-639a-497f-80d1-c1ccb50399b7.jpg


HOT WATER is the key here (no little ones here, so the hot water is hot...like 180-185F)...dry it with a towel, "fling-n-sling" the tube, (if you have compressed air to blow out the little creases, all the better) and it's dry in about 2 minutes.


    
This message has been edited by gubb33ps from IP address 162.192.93.122 on May 1, 2017 6:27 PM


 
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SteveV
(Login stevevines)
Crosman Forum Member
174.49.53.186

Ray, Gubbs is right -

May 7 2017, 6:49 AM 

Disassemble the gun to just the tube/will fill valve & end-cap. Use hot water, and hose your gun down with Rem-oil or something similar before dunking, and it's easy-peasy to dry after the fact. The quickest way to find a leak.

 
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James Perotti
(Login jpsaxnc)
Crosman Forum Member
71.71.83.71

Iv'e done this on co2 and pcp guns. Take the action out of the stock,

May 1 2017, 5:46 PM 

remove the hammer and spring, fill the tub or sink with water, submerge the action, and see where the bubbles come out. The action is pressurerized water will not enter it. hth.

 
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ray1377
(Login ray1377)
Crosman Forum Member
71.143.248.32

Well I got her pressurized back up and

May 1 2017, 9:16 PM 

put the balloons on her this evening.
I'll check it in the morning before work.
I hope it works. If it doesn't, I'll be giving her a "HOT" bath.happy.gif
Thanks for the info fellows.
Ray

 
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SteveV
(Login stevevines)
Crosman Forum Member
174.49.53.186

Valve stem seals can leak as well -

May 2 2017, 4:40 AM 

If the valve stem isn't sealing well it will leak. That was the culprit on my hpa'd 2260.

 
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ray1377
(Login ray1377)
Crosman Forum Member
107.77.68.98

Well I checked it

May 2 2017, 8:02 AM 

This morning before work and both the balloon on the barrel and fill fitting were deflated and their was 1200 psi gone. So I'm guessing its not the filler port check valve or the exhaust valve stem. I stretched a balloon over the pressure gauge a d filled it to 1500 psi again. I'll check it after work. Thanks for all the input so far. I appreciate it.
Ray

 
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Bio
(Login Biohazardman)
Moderator
71.236.167.69

Re: Well I checked it

May 7 2017, 8:05 PM 

Balloons are great on the barrel of an assembled gun to check for valve leaks but they don't give any indication of a leak if your valve and your T-port are both leaking. Once again water is your friend filling the exhaust port of the valve with a little will let you know in short order if there is a leak.
I used to have a life. But now I have the forum. I am a sick man?

[linked image]

 
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