Seals on a Crosman 357

[fantumfan2003]

I noticed some of us have the 357s here and thought this useful piece on its seals from Guru Tim McMurray would help.

http://www.network54.com/Forum/275684/m ... estoration

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The 357 is pretty much a throwaway but it can be rebuilt if you go after all the areas where they fail. To just put one part in will virtually gaurantee you having to go inside again soon so you may as well do it right.
There are 9 parts that will need to be changed out if you want your 357 to a have a new lease on life.
You should get 5000-8000 rounds thru a 357 without any issues if you store it empty and don't abuse it.
I'd also leave the barrel unlatched for storage.

38-A027 Piercing pin
38-128 End Seal
These two parts should always be changed out as a set for best results. Overcompression of the end seal is extremely common and should be avoided. Cranking any CO2 as hard as you can is always a bad idea.

357-035 Cyl. Plate
The tab that pushes the index pawl forward acting as a spring gets fatigued and will eventually fail to get the pawl to engage cylinder to rotate it.

357-021 Latch support
This is a piece of mushy plastic acting as a spring. It will eventually take a set and the barrel will not latch home securely. This is why I advise you to leave barrel open when not in use to take some of the tendency away for this part to overcompress over time.

2 each 357A054 Quad seals
These seals suffer from the bends and should not be left with pressure on them for long periods. They are simply not up to the task and they will eventually extrude.

38-130 oring
This 70 durometer Urethane oring is in the bottom of the valve and needs to be changed out when you do an overhaul. It is also a reason the gun should not be left charged and will be toast is you try to leave pressure on it for extended periods.

357-053 lever bushing(brass)
Early 357's had a nylon bushing that went mushy after a few thousand rounds giving you poor indexing as you are experiencing. The replacement part is brass and will not suffer the same failure as the early nylon bush.

357-041 Exh Valve seal
When you take the valve apart this seal is rarely salvageable so it is the seal that needs to be changed whenever you go inside the valve.

Pretty much all these parts give up at about the same time so if you try to go after the problem you're expereincing other problems will quickly follow. If you don't throw the thing away and buy a new one for $48 you will want to change out these 9 parts and then you can trust the gun like it is new.

Later

Tim

Mac1 Airgun

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He has the seals so does Alan of AB Airguns

M.

[fantumfan2003]

I have got mine working. And shoots well too. Had to change all the seals including ones inside the valve where the slow leak was.

Pics later. No chrony to give fps figures.

I am happy about the fact that I got it working where as when I purchased it I was just hoping to have it in my hands.

Just a note. CO2 is complicated business and should not be attempted without prior homework. I literally trawled on network54 and exchanged notes with a couple of people here before attempting the re-seal.

Here is a picture of the valve opened with the old seals in the top row and the new ones in bottom row. Yes the powder you see is the old seal, or what was left of it.



Now I want to paint it. Need help with an optimum way to paint it.

M.