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All Springer/NP/PCP Air Gun Discussion General > Vintage Air Gun Gate
Crosman 1400 weird air leak
Volvoguy:
Thanks eveyone. I didn't know you could replace it with an o-ring so I may try that if the problem continues. It's just a very odd problem. I did find a place that seems to have the proper quad seal in bulk as well, though I wonder why mine failed. If the problem is the brass housing and retaining ring, then putting in another seal won't do any good.
It held perfect pressure for 24 hours, though this time when pumped it did not hiss at me, so maybe I need to let it sit when it starts leaking after pump 5.
Another thing it started doing is blowing the bolt open when fired. Twice I had the bolt lift and open which suprised me. I may need a thicker o-ring to keep it in place. The o-ring I used on my 140 bolt failed to seal so I don't know how well this kit does with matching.
Volvoguy:
--- Quote from: threesuns on March 25, 2023, 08:07:30 AM ---When I resealed my 1rst variant 760, someone suggest an O-ring, to replace the quad seal. I don’t know if they would be the same size as for a 140/1400. Maybe some else can confirm.
--- End quote ---
Do you know why they reccomended an O-ring instead of the original quad? This rifle has a pretty tall quad seal so I wonder if it'll work. In my assorted o-ring kit I don't see anything that will obviousally work but I will have to try it sometime.
I have a leaking rifle (can't recall the model but it is a newer pump), so I can also try it on that one as well.
Blowpipe Sam:
Baker airguns and Mac1 will sell you multiples of the quad ring. Just ask them for some.
I suggest some moly paste on the trigger and sear components. The smooth function of the sear and the trigger is important for proper sealing of the valve cap. I’d check the nipple on the valve for nicks or dings but that’s unlikely.
Can you hear or feel the valve cap physically setback and seat against the sear on the first or second pump? Some guns make an audible click.
It sounds like you might be pumping too fast?
Because of the pump design 1400’s make the most power when pumped slowly. When you extend the pump arm you should hear a momentary hiss as the somewhat restricted intake port admits air past the piston. I always pause and count “1 Mississippi” at the top of every stroke to make sure the pump chamber completely fills. You should hear/feel the valve cap setback at the end of the pump stroke. Resistance should start building after the third pump and the last two should be pretty hard to stuff in there.
If you don’t hear that hiss when you open the pump it’s time for some oil.
Hope some of this helps.
Oh yeah. The blowing the bolt open thing is a problem. A new O’ring helps but best to get in the habit of making sure the bolt is flipped all the way down before shooting. I prefer the 140 style breech cover on my first model. It’s much more secure.
Volvoguy:
--- Quote from: Blowpipe Sam on March 26, 2023, 01:27:01 AM ---Baker airguns and Mac1 will sell you multiples of the quad ring. Just ask them for some.
I suggest some moly paste on the trigger and sear components. The smooth function of the sear and the trigger is important for proper sealing of the valve cap. I’d check the nipple on the valve for nicks or dings but that’s unlikely.
Can you hear or feel the valve cap physically setback and seat against the sear on the first or second pump? Some guns make an audible click.
It sounds like you might be pumping too fast?
Because of the pump design 1400’s make the most power when pumped slowly. When you extend the pump arm you should hear a momentary hiss as the somewhat restricted intake port admits air past the piston. I always pause and count “1 Mississippi” at the top of every stroke to make sure the pump chamber completely fills. You should hear/feel the valve cap setback at the end of the pump stroke. Resistance should start building after the third pump and the last two should be pretty hard to stuff in there.
If you don’t hear that hiss when you open the pump it’s time for some oil.
Hope some of this helps.
Oh yeah. The blowing the bolt open thing is a problem. A new O’ring helps but best to get in the habit of making sure the bolt is flipped all the way down before shooting. I prefer the 140 style breech cover on my first model. It’s much more secure.
--- End quote ---
I have the gun taken somewhat apart at the moment. I remoced the barrel and sometimes with one pump it will cock, but usually on the second pump it will click and I can see the components move. I will lube the tripper components up more and see what it does. If that doesn't get it then I guess I will have to take it 100% apart again which I have gotten a little tired of doing. Both the 140 and this 1400 have had to be apart several times.
The 140 sure does have a better breach. I replaced the O ring on my 1400 again and it has gotten a little better, but not as good as it should be.
Glasstomb:
--- Quote from: threesuns on March 25, 2023, 08:07:30 AM ---When I resealed my 1rst variant 760, someone suggest an O-ring, to replace the quad seal. I don’t know if they would be the same size as for a 140/1400. Maybe some else can confirm.
--- End quote ---
From Mac1:
An O-ring will work in the Cap for a while but the proper seal is a Quad seal.
I've used these: https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_2205_111_115&products_id=5042
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