GTA
All Springer/NP/PCP Air Gun Discussion General => American/U.S. Air Gun Gates => Crosman-Benjamin Air Gun Gate => Topic started by: basednibbba on December 16, 2019, 10:58:52 PM
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Hello. I got a new Crosman 1322 and have dis/re assembled it several times now. Some trial and error was incurred. The valve stem assembly (part number 760-145) broke in the following way: The delrin portion (the plastic spring guide and valve seal) broke in two sections. I got some more life out of it by using JB plastic bonder to re-attach the seal part to the spring guide part. Later, like a stupid ape, I once again hammered on the wooden dowel I was using to remove the valve, shock loading the stem, and producing the same failure as before. I have learned many lessons.
I was able to re-fasten the stem assembly again, but now the valve is holding no air at all. It expels all of the air through the transfer port, and consequently the barrel, upon the completion of a single stroke of the pumps arm. I have already ordered a replacement part number 760-145 and hope it will remedy the problem. There is some other minor damage to the valve in the form of a couple of deep scratches in its aluminum surface likely produced by the burrs on the roll pin hole in the front of the pump tube (which I have since removed).
Also, while banging on the valve from the wrong end, I dented the back of the valve, creating a burr in the aluminum which I have removed. The burr was most likely created by the aluminum impacting the steel dimple in the pump tube, which I think is there to properly locate the valve in the pump tube. Supporting this idea, I have noticed that the front frame screw is slanted when I decide to take apart the gun, suggesting that air pressure has pushed the valve back slightly further than the manufacturers intended. This is not optimal, because the transfer port will be slightly out of alignment.
Looking at the seals. The 130-035 o-ring has a shallow chip in it that almost spans half the diameter (not quite). I have decided I should replace the 130-035 o-ring just in case. The transfer port O-ring (part# 130-036) also appears to be compromised, and will need replacement. The pump cup (760-140) appears to be in perfect condition. I am testing its quality anyways by leaving the pump cocked for a while, to see how far the arm drops, if at all. One other thing I have noticed is the valve bodies threads seem looser. They were very tight at the beginning.
I tried the classic air leak test (soapy water on sealed areas) to see if bubbles would pop up in the affected areas. I suppose I should have expected the result (the valve holds no air), but their were no signs of a leak. Perhaps I have a poor understanding of this weapon and someone could give me advice or relate a similar story. Thank you for reading.
UPDATE: I am waiting for the valve stem assembly to arrive. Some new quirks have come up. I installed a new 130-035 o-ring on the valve. The original problems persist, except that after the installation of the new o-ring, the piston began making a harsh creaking sound (like the noise a ratchet screw driver makes) when the piston nears the end of the stroke. I thought that it could have been some sort of rough texture in the pump tube, so I did a tiny amount of sanding.
The noise persisted, so I put lube on the sides of the pump cup, and even some lube on the 135-035 o-ring (possibly a mistake). I also noticed that the pump arm pin had a groove in the center with sharp burrs on either side, I guess just from pumping it, so I did a couple of minutes sanding on the pin with medium grade sand paper. In the end, the pump was moving more smoothly, but I don’t know if this is a good thing. The piston doesn’t offer much resistance at this point, much less than before. It still makes a “pop” noise when it is pulled out of the pump tube though.
This lower resistance could be because the valve stem is deteriorating further, I am not sure. In its current state, I can still hear air coming through the transfer port at the end of the pump stroke. Thinking that I may have over lubed the gun, I tried to remove most of it, but the same low resistance is given by the piston. The threads on the valve are now only hand tight, so I think that over lubing may be the latest problem. Thank you for reading.
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Hello. I got a new Crosman 1322 and have dis/re assembled it several times now. Some trial and error was incurred. The valve stem assembly (part number 760-145) broke in the following way: The delrin portion (the plastic spring guide and valve seal) broke in two sections. I got some more life out of it by using JB plastic bonder to re-attach the seal part to the spring guide part. Later, like a stupid ape, I once again hammered on the wooden dowel I was using to remove the valve, shock loading the stem, and producing the same failure as before. I have learned many lessons.
I was able to re-fasten the stem assembly again, but now the valve is holding no air at all. It expels all of the air through the transfer port, and consequently the barrel, upon the completion of a single stroke of the pumps arm. I have already ordered a replacement part number 760-145 and hope it will remedy the problem. There is some other minor damage to the valve in the form of a couple of deep scratches in its aluminum surface likely produced by the burrs on the roll pin hole in the front of the pump tube (which I have since removed).
Also, while banging on the valve from the wrong end, I dented the back of the valve, creating a burr in the aluminum which I have removed. The burr was most likely created by the aluminum impacting the steel dimple in the pump tube, which I think is there to properly locate the valve in the pump tube. Supporting this idea, I have noticed that the front frame screw is slanted when I decide to take apart the gun, suggesting that air pressure has pushed the valve back slightly further than the manufacturers intended. This is not optimal, because the transfer port will be slightly out of alignment.
Looking at the seals. The 130-035 o-ring has a shallow chip in it that almost spans half the diameter (not quite). I have decided I should replace the 130-035 o-ring just in case. The transfer port O-ring (part# 130-036) also appears to be compromised, and will need replacement. The pump cup (760-140) appears to be in perfect condition. I am testing its quality anyways by leaving the pump cocked for a while, to see how far the arm drops, if at all. One other thing I have noticed is the valve bodies threads seem looser. They were very tight at the beginning.
I tried the classic air leak test (soapy water on sealed areas) to see if bubbles would pop up in the affected areas. I suppose I should have expected the result (the valve holds no air), but their were no signs of a leak. Perhaps I have a poor understanding of this weapon and someone could give me advice or relate a similar story. Thank you for reading.
UPDATE: I am waiting for the valve stem assembly to arrive. Some new quirks have come up. I installed a new 130-035 o-ring on the valve. The original problems persist, except that after the installation of the new o-ring, the piston began making a harsh creaking sound (like the noise a ratchet screw driver makes) when the piston nears the end of the stroke. I thought that it could have been some sort of rough texture in the pump tube, so I did a tiny amount of sanding.
The noise persisted, so I put lube on the sides of the pump cup, and even some lube on the 135-035 o-ring (possibly a mistake). I also noticed that the pump arm pin had a groove in the center with sharp burrs on either side, I guess just from pumping it, so I did a couple of minutes sanding on the pin with medium grade sand paper. In the end, the pump was moving more smoothly, but I don’t know if this is a good thing. The piston doesn’t offer much resistance at this point, much less than before. It still makes a “pop” noise when it is pulled out of the pump tube though.
This lower resistance could be because the valve stem is deteriorating further, I am not sure. In its current state, I can still hear air coming through the transfer port at the end of the pump stroke. Thinking that I may have over lubed the gun, I tried to remove most of it, but the same low resistance is given by the piston. The threads on the valve are now only hand tight, so I think that over lubing may be the latest problem. Thank you for reading.
I am having almost the same issues. How did you resolve this. I have the burs in the valve. I also steel wooled the air tube. Is it possible I removed too much material.
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Hello Nial and welcome to the forum! 8)
Based on what you have written and the amount of force you describe, here are my thoughts..
The valve stem was ruined once it broke. From what you describe, it sounds like you applied a lot of pressure to it when you used a dowel the bang it out. if it was enough to break the derlin section of it inside, there may have been damage to the stem itself, slight bend or bow possibly? That creaking noise you hear is from air still getting past the seat of the valve stem. I have valves with lighter springs in them and if I do not cock the gun first, that is exactly how it sounds.
The valve body itself is ruined. The indent inside the pump tube is there to prevent the valve from moving backwards while pumping. If you tried to pound the valve out in that direction, hard enough that you "dented" the back ledge of the valve, it means that the valve can now move back further then it is supposed to. This will cause head space between the valve and the piston cup and it will also cause the front trigger frame screw ( the one that holds the valve in place) to bend and break off. Sorry to have to say it, but the valve itself needs to be replaced. when pushing out the valve, use something that is strong enough that is hollow. position it against the valve so that the exposed end of the valve stem sits safely inside the hollow tube. This will let you push out the valve without making contact with the stem. The scratches on the valve body are really of no concern, if that had been all that was wrong, but you have other issues with it that are.
O-rings and burr. Crossman is notorious for sharp edges in the stamped tubes. When you take the gun apart again, debur all holes, slots, and grooves. If you do nothing else... debur the pump arm linkage slot and the pivot pin holes. Any cracks, slices, or chunks missing from your o-rings from dis-assembly / re-assembly and they are ruined. A diamond file, fine round stone, or even medium to fine sandpaper wrapped around a small diameter dowel or pop sickle stick works just fine. Any method that works for you and gets the job done will make it better than it was.
Do a search online for 1322 dis-assembly videos. There are so many out there for you to learn from. Here are a couple I found from a quick search. ;)
https://www.bing.com/videos/search?&q=crosman+1377+pump+cup&docid=608048299450435579&mid=C04191767D1890F5BEC7C04191767D1890F5BEC7&view=detail&FORM=VDRVRV&ajaxhist=0 (https://www.bing.com/videos/search?&q=crosman+1377+pump+cup&docid=608048299450435579&mid=C04191767D1890F5BEC7C04191767D1890F5BEC7&view=detail&FORM=VDRVRV&ajaxhist=0)
https://www.bing.com/videos/search?q=how+to+disassemble+crosman+1322&view=detail&mid=239FD47C35D2497D82B9239FD47C35D2497D82B9&FORM=VIRE (https://www.bing.com/videos/search?q=how+to+disassemble+crosman+1322&view=detail&mid=239FD47C35D2497D82B9239FD47C35D2497D82B9&FORM=VIRE)
Good luck to you and I hope you get it back up and working. ;)
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I am having almost the same issues. How did you resolve this. I have the burs in the valve. I also steel wooled the air tube. Is it possible I removed too much material.
The inside of the pump tube is smooth and shiny if you noticed. Remember, there is a rubber pump cup that slides back and forth in there. If you rough up the inside, it could cause premature wear on the pump cup. If you rough it up enough, it could cause air to leak out behind it as you pump. Debur the edges of the holes and slots, but probably best not to mess with the inside surface of the pump tube. ;)
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I am having almost the same issues. How did you resolve this. I have the burs in the valve. I also steel wooled the air tube. Is it possible I removed too much material.
The inside of the pump tube is smooth and shiny if you noticed. Remember, there is a rubber pump cup that slides back and forth in there. If you rough up the inside, it could cause premature wear on the pump cup. If you rough it up enough, it could cause air to leak out behind it as you pump. Debur the edges of the holes and slots, but probably best not to mess with the inside surface of the pump tube. ;)
Okay good advice as I learn. I did the pump cup lever arm test and the pump cup is sealing. I think the tube is still okay but the valve or orings must be leaking air....
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To test a valve for leaks, give the valve a few pumps then remove it from the gun, drop it in a glass of water. If no bubbles, then the leak is not in the valve but the external orings that seal the valve to the tube. The valve can be discharged by hitting the valve stem with a larger plastic screwdriver handle or plastic mallet, careful to keep hand parts away from the port opening, wear gloves.
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To test a valve for leaks, give the valve a few pumps then remove it from the gun, drop it in a glass of water. If no bubbles, then the leak is not in the valve but the external orings that seal the valve to the tube. The valve can be discharged by hitting the valve stem with a larger plastic screwdriver handle or plastic mallet, careful to keep hand parts away from the port opening, wear gloves.
If it bubbles, remind yourself it's not Alka Seltzer :-*
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I use a crossbow bolt with the point and knock removed, to push out valves, the hole in the carbon fiber tube clears the poppet stem.
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I use a crossbow bolt with the point and knock removed, to push out valves, the hole in the carbon fiber tube clears the poppet stem.
I have a junk barrel I use. Cat skinning 102
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Excellent senior experiences.
I believe I damaged the stem/derin the first time I banged out the valve. I started with the barrel like the video I watched and then had the dowel waiting for the steel wool polish and like a dummy assumed it would be better to tap with wood instead of (hollow) steel......
I also enlarged the volume of the exhaust side by smoothing out threads near the stem pocket and either removed some material inside the stem or didn't get enough material blown out and there must be that microscopic piece of material causing the derin not to be flush.
Tonight I cleaned the inside of the valve for fine debris. Almost got a seal. I mixed some JB Weld and spun the derin end of the stem like a dipped ice cream cone in the JB to add a thin layer. I will fine sand to an airtight seal and try again tomorrow. I also ordered the Mellon Air FT Piston and Valve as a back up plan. Worst case I can chrono both valves.