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Pumper aired up but wont fire - help!

December 10 2011 at 5:38 PM
  (Login flytie)
Crosman Forum Member
from IP address 69.245.17.123

 
I replaced valve seals and lined up the holes on valve upon install.

Pumped her up with 7 pumps and "click" - nothing.

Took hammer and spring out and put a dowell on the exhaust valve stem. Pushed on it and it goes down a half inch or so then springs back - nothing!

How do I release the air from tube? Do I take the pump assembly and plunger off and use a dowel to depress the inlet valve?

If you fellas have any ideas as to what could be wrong and fixes I'd appreciate the advice.

Drew

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(Login robnewyork)
Crosman Forum Member
98.14.114.201

its gonnna be loud

December 10 2011, 5:43 PM 

what model is it

 
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(Login pneuguy)
Crosman Forum Member
74.242.252.49

From your description of how you opened the valve with a dowel...

December 10 2011, 6:13 PM 

...it doesn't seem possible that the valve is pressurized. What makes you think it is?

Another question: How much time did you allow to elapse between pumping and firing? An air leak might have allowed the charge to escape during that interval.

But in any case, it definitely sounds like it's empty now.

Steve

 
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(Login robnewyork)
Crosman Forum Member
98.14.114.201

good point steve .nt

December 10 2011, 6:56 PM 


 
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(Login Arkmaker)
Crosman Forum Member
74.170.102.119

Did yo uput the o-ring back on the OD of the Valve?

December 10 2011, 6:36 PM 

nahh......I'm sure you would have heard air escaping if that were the case.

 
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(Login flytie)
Crosman Forum Member
69.245.17.123

Yeah, I did

December 10 2011, 9:44 PM 

I put the orings in respectively.

Its hard as hell to pump thats how I know the tube is charged! Or, at least it feels like it is. Prior, the gun would pump and shoot but hiss so I replaced the seals. The power was respectable prior to seal replacement.

Drew

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(Login jct842)
Crosman Forum Member
216.134.239.168

spring back?

December 11 2011, 5:42 PM 

the only thing that the dowel hit springs it back? the valve stem will not spring back with air behind it. I don't think you have air in the valve, you may feel resistance, and it could be the check valve is not opening to let air in too.john

 
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dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

Couple of thoughts

December 12 2011, 12:01 PM 

I dont recall seeing if you did any valve work or changed springs, so I'm guesing..... but if you changed the internal valve spring, youi may need to cock it forst, then pump it

Spring back? if you feeling like you fight the pump arm after a couple of pumps, then the check valve is not sealing back and allowing any air in the valve to get back out into the pumpt tube, and get out..



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(Login flytie)
Crosman Forum Member
69.245.17.123

I replaced the valve/seals

December 12 2011, 12:35 PM 

To clarify: i repalced the valve seals both exhaust and inlet. Re-assembled making sure to align the exhaust port correctly. Put a few pumps in her until the valve sealed. Then put 6 pumps in with effort increasing with each pump. Cocked and fired several times nothing happened. Took the hammer spring out and inserted a dowel onto the hammer and, with muzzle protected on the floor, pressed down on the exhaust valve pin. The resistance is much more pronounced than with no air or 1 or 2 pumps. It springs back into position after each depression but no air release.

Should I remove the pump linkage and depress the inlet valve to release any air that may reside in the tube? Whats the best and safest way to go about this?

Drew

[linked image]

 
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(Login pneuguy)
Crosman Forum Member
74.242.252.49

Weird. It's really hard to believe there's any way...

December 12 2011, 2:58 PM 

...the valve would hold pressure - without at least releasing it slowly - if you're really pushing the exhaust valve open as you say. Even if the transfer port was somehow plugged solid, air would still leak out around the stem when the valve is held open.

In any case, if the valve is really pressurized like you think it is, it will be very hard to push the check (inlet) valve open against the force of accumulated pressure. The checkvalve is large and can only be accessed through the inlet hole. Even if you can push hard enough with a needle punch or similar tool, the concentrated force will probably damage the valve.

Another approach would be to remove the valve body and s-l-o-w-l-y unscrew the two halves. After just a turn or two, any contained pressure should begin to escape with a hiss. At least this is what happens with 392 valves.

Steve


    
This message has been edited by pneuguy from IP address 74.242.252.49 on Dec 12, 2011 3:14 PM


 
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(Login Voltar1)
Crosman Forum Member
72.25.192.4

there is no way what you describe can occur

December 12 2011, 3:17 PM 

valve springs back and easiest with air in valve.... no way

btw what pumper is this?

 
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(Login flytie)
Crosman Forum Member
69.245.17.123

its much harder to depress the exhaust valve pin

December 12 2011, 8:58 PM 

with 7 pumps in her than with none! Something is causing the resistance and I can only assume air in the tube! Added to that the difficulty in pumping effort.

Steve, you mention unscrewing the valve retaining nut and allowing air to escape vs depressing the inlet valve. How many turns should I give the nut? Is it possible to have "valve hammer" ocurr against the retaining nut assuming it doesn't move with the nut? This gives me the willies!

Drew


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(Login pneuguy)
Crosman Forum Member
74.242.252.49

Drew, for no adequate reason, I was assuming your gun is one...

December 12 2011, 9:02 PM 

...that has a Crosman-style cartridge valve body (e.g., 392 or 1377) that consists of two halves that screw togther with an O-ring seal, and that can be removed from the gun as one piece, then allow the two halves to be slowly unscrewed from each other outside the gun.

My suggestion is only as valid as that assumption.

So. To ask an overdue question (that Walter already did): What kind of gun are you working with?

Steve


    
This message has been edited by pneuguy from IP address 74.242.252.49 on Dec 12, 2011 9:04 PM


 
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dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

I made that assumption too

December 13 2011, 9:08 AM 

After all, it is the Crosman forum and Crosman has a long line of guns using "cartridge" valves......

Just hoping its something we've seen before, and not another set conditions to add to our diagnostic charts.....



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
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(Login flytie)
Crosman Forum Member
69.245.17.123

Sheridan/Benji style valve

December 13 2011, 4:12 PM 

Has inlet with seal + spring + exhaust w/pin and seal going into brass body. This entire assmbly drops into gun and is held in place with a threaded nut.

Hope this helps.

Drew

[linked image]

 
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dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

yea, then you should be able to get it out

December 13 2011, 4:29 PM 

like Steve described.

Caution though is strongly advised. No injuries allowed.



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

 
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(Login pneuguy)
Crosman Forum Member
74.242.252.49

What Dan said. Just remove the stud (what you're callling a "nut") and...

December 13 2011, 9:46 PM 

...(assuming the gun is a Benji or Dan) pop the valve out with air pressure by closing the pump arm.

Unfortunately, there's still no way the combination of symptoms you describe make any sense.

Steve


    
This message has been edited by pneuguy from IP address 74.242.252.49 on Dec 13, 2011 9:46 PM


 
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(Login Voltar1)
Crosman Forum Member
72.25.192.4

Drew, make any headway on your valve troubles?

December 20 2011, 9:42 AM 

curious what you have found so far?

 
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(Login flytie)
Crosman Forum Member
69.245.17.123

Yes..

December 20 2011, 10:32 PM 

Sorry about the delay fellas just sorting things out. I really do appreciate all your help!

Heres the scoop: the seal in the exhaust valve came loose on the pin and maintained a seal. I had to take out the pump assmbly and depress the inlet valve to release the air. It worked! Cleaned everything real good, replaced the exhaust pin seal and all is working fine now.

Such a rare happening; Never seen it before. One thing for sure: I knew the chamber was under pressure because the exhaust valve was "stiff" and the pump effort was progressively harder. Did not want to take any chances!

Whew!!

In Friendship,

Drew

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