What would cause a pumper to leak with one or two pumps but not 3 or more?
Other Zoraki Ultra leaks on first two pumps but not the 3rd
- Thread starter borne2fly
- Start date
have you put oil in the cylinder 2 or 3 drops could solve your problem
https://www.pyramydair.com/airgun-r...0uN4L05QCfshCUh828Mj2QIw4fcSgi6tuA2LJntNPICro
https://www.pyramydair.com/airgun-r...0uN4L05QCfshCUh828Mj2QIw4fcSgi6tuA2LJntNPICro
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I just tried that. With enough oil it now appears to seal after 2 pumps instead of 3.
But that took something like a teaspoon of oil, not just a few drops.
Is that normal?
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Unfortunately it could be a number of seals borne2fly. There are 2 seals on the first stage pump head (inner and outer), and another 2 at either end of the first stage cylinder-
You then have the second stage pump u cup, with an oring under the head which acts as a check valve (allowing the primary pressure into the secondary chamber).....
You then have the pre plenum check valve which has 3 more o rings, one sealing the valve seat to secondary cylinder, one sealing it to the valve body, and one on the poppet.
Sorry fella but the only real way to know is to start going through them as its hard to get an indicator of which one is letting by (unless youre getting a hiss at the end of the stroke and there is oil visible on the outside of the secondary cylinder, then it 'might be' seal 4200 on Bagnall and kirkwood's exploded diagram)
You then have the second stage pump u cup, with an oring under the head which acts as a check valve (allowing the primary pressure into the secondary chamber).....
You then have the pre plenum check valve which has 3 more o rings, one sealing the valve seat to secondary cylinder, one sealing it to the valve body, and one on the poppet.
Sorry fella but the only real way to know is to start going through them as its hard to get an indicator of which one is letting by (unless youre getting a hiss at the end of the stroke and there is oil visible on the outside of the secondary cylinder, then it 'might be' seal 4200 on Bagnall and kirkwood's exploded diagram)
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Thank you for that breakdown. I don’t mind pulling everything apart if I have some idea what to look for. Who sells seal kits for this?Unfortunately it could be a number of seals borne2fly. There are 2 seals on the first stage pump head (inner and outer), and another 2 at either end of the first stage cylinder-
View attachment 492564
You then have the second stage pump u cup, with an oring under the head which acts as a check valve (allowing the primary pressure into the secondary chamber).....
View attachment 492563
You then have the pre plenum check valve which has 3 more o rings, one sealing the valve seat to secondary cylinder, one sealing it to the valve body, and one on the poppet.
View attachment 492565
Sorry fella but the only real way to know is to start going through them as its hard to get an indicator of which one is letting by (unless youre getting a hiss at the end of the stroke and there is oil visible on the outside of the secondary cylinder, then it 'might be' seal 4200 on Bagnall and kirkwood's exploded diagram)
With so many seals I imagine that one should expect to be replacing these on a fairly regular basis. Plenty of moving parts in there to wear out.
With car engines I always squirted some oil into the cylinder to check if it brought the compression back up (ring and valve check). Doing the same thing here does appear to have a similar effect. The main surprise for me is that this is happening with barely a thousand shots ever fired with this gun.
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The oring kits are available, but unfortunately I could only find two sources for the U cup seals.....a company in France and the other a polish seller on ebay, but from both it was looking close to £100 plus posted to the UK 
I opted to swap out all of the U cup seals (apart from the secondary main seal) with orings, and can confirm that they're functioning just fine.
For the secondary main seal I found and used this u cup....
Which measures slightly taller than the original, but fits and functions spot on too
Sorry but I didn't take notes of the orings used, just dived in to the huge stash I've gathered over the years and used what fitted.....Good luck with yours borne2fly
I opted to swap out all of the U cup seals (apart from the secondary main seal) with orings, and can confirm that they're functioning just fine.
For the secondary main seal I found and used this u cup....
Which measures slightly taller than the original, but fits and functions spot on too
Sorry but I didn't take notes of the orings used, just dived in to the huge stash I've gathered over the years and used what fitted.....Good luck with yours borne2fly
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Thank you Jamie! I will follow your leadThe oring kits are available, but unfortunately I could only find two sources for the U cup seals.....a company in France and the other a polish seller on ebay, but from both it was looking close to £100 plus posted to the UK
I opted to swap out all of the U cup seals (apart from the secondary main seal) with orings, and can confirm that they're functioning just fine.
For the secondary main seal I found and used this u cup....
View attachment 492665
Which measures slightly taller than the original, but fits and functions spot on too
Sorry but I didn't take notes of the orings used, just dived in to the huge stash I've gathered over the years and used what fitted.....Good luck with yours borne2fly
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I have to ask …. Why would it leak with only one or two pumps but stop leaking with 3 or more?
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At a guess......I'd have to go with either the 2nd stage pump cup having hardened, or the oring that sits under that piston nose. The first stage pushes the atmospheric air in front of that seal, so if either have hardened the air will just return back in to the 1st chamber. If the first 2 pumps were to compress just a very small amount of air into the 2nd chamber it 'might' be enough to flare the hardened u cup seal/ force the nose back onto the oring to allow the following pumps to all charge.
Just a guess of course, but when I had leaks at either ends of the 1st and 2nd stage cylinders, you could hear the air escaping as it had been pressurised. If it is the 2nd stage u cup thats passing, you won't hear the air returning to the first stage cylinder.....
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Hardened seals ... I was thinking that too. Who knows how long this thing just sat around before it eventually got shipped?
I have other guns that use U-cups as well, and I've also replaced them with O-rings wherever I could. McMaster-Carr does sell a few U-cups but the sizes are limited, while their O-ring selection is much broader.
It seems to have stopped leaking at two pumps after flushing through enough oil. I never use less that two pumps so I'm gonna run it as is until that changes. Meanwhile, might as well collect seals for the eventual rebuild.
On a positive note, the Zoraki is amazingly accurate. It compares with some rifles at normal pistol ranges.
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the seal on the pistol are all odd and they have been talked about a lot
now there is a company that is making the seals in Poland and they are on Ebay and they what an arm and a leg for them
the factory does not care to help and the main UK parts sellers Knibbs and Chambers do not care them
so why did i say to oil the cylinder
because it is the easiest thing to do, a few drops of oil is a hell of a lot quicker then tearing the damn gun apart and the Zoraki i would say is far more complicated to work on compared to Daisy 7-7 or a Crosman 1377
all SSP and multi stroke guns need oil and a few drops will bring most back to life
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2505460.m570.l1313&_nkw=zoraki+seals&_sacat=0
now there is a company that is making the seals in Poland and they are on Ebay and they what an arm and a leg for them
the factory does not care to help and the main UK parts sellers Knibbs and Chambers do not care them
so why did i say to oil the cylinder
because it is the easiest thing to do, a few drops of oil is a hell of a lot quicker then tearing the damn gun apart and the Zoraki i would say is far more complicated to work on compared to Daisy 7-7 or a Crosman 1377
all SSP and multi stroke guns need oil and a few drops will bring most back to life
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2505460.m570.l1313&_nkw=zoraki+seals&_sacat=0
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Eureka!
Doesn't appear to be the seals after all .... it seems I can stop the leaking by pushing forward on the valve stem, even after just one pump.
Not sure what the prescribed fix for this would be, though.
Doesn't appear to be the seals after all .... it seems I can stop the leaking by pushing forward on the valve stem, even after just one pump.
Not sure what the prescribed fix for this would be, though.
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That's a result borne2fly, happy days
Here is a pic of the valve assembly (yours won't have the delrin washer/ oring, as above I swapped out the original valve stem seal on mine).
The valve return spring is pretty mighty, but oiling the system doesn't always reach the valve stem seal as the brass washer is a precision fit to the stem. Try adding a couple of drops to the outside of the stem by the hammer and working it by hand. Sounds like it's hanging up there (assuming your hammer is setting as you first open the pump and not holding the valve open too?)
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You nailed it!That's a result borne2fly, happy days
Here is a pic of the valve assembly (yours won't have the delrin washer/ oring, as above I swapped out the original valve stem seal on mine).
View attachment 493157
The valve return spring is pretty mighty, but oiling the system doesn't always reach the valve stem seal as the brass washer is a precision fit to the stem. Try adding a couple of drops to the outside of the stem by the hammer and working it by hand. Sounds like it's hanging up there (assuming your hammer is setting as you first open the pump and not holding the valve open too?)
A bit of oil on the stem was all it took.
I now have a properly working pistol.
Thanks!
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