Crosman 150 Valve Seat Polishing

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JKT

JKT

Member
May 18, 2019
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Kansas
I have spent many hours and various valve seals but my Crosman 150 valve will not seal. I suspect that the valve seat itself may have some damage that keeps it from forming a good seal. Has anyone tried to polish or recut the seat in the end of the valve?
IMG_6680.jpeg
 
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Yes, an abrasive slurry can be used to work down a defect in the poppet face and/or valve seat. Color both surfaces with a black Sharpie so you can monitor your progress. A low spot or scratch will remain colored.

Just be mindful of the potential to overheat the poppet material. Go slow...or if the seat is in really bad condition, you can temporarily glue a flat washer to the poppet face to protect it.
 
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nervoustrig said:
Yes, an abrasive slurry can be used to work down a defect in the poppet face and/or valve seat. Color both surfaces with a black Sharpie so you can monitor your progress. A low spot or scratch will remain colored.

Just be mindful of the potential to overheat the poppet material. Go slow...or if the seat is in really bad condition, you can temporarily glue a flat washer to the poppet face to protect it.
Click to expand...
Should the seat face be sharp, so it cuts into the seal material slightly? Looking at the seat of my 150 valve it does look like it should be sharp, not flat, so it penetrates the seal material slightly.
I am thinking I need to use something with an angled face to polish the face of the seat to ensure I keep the same profile.
 
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If the valve assembly shown in the photo is the one you are having issues with sealing, I strongly suggest you replace the o-ring with a 112 urethane one before you attempt any modifications to valve seat or poppet valve to see if that solves your problem. The one shown appears to be very questionable.

The original valve seats appear to be flat or nearly so.
 
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mreynolds said:
If the valve assembly shown in the photo is the one you are having issues with sealing, I strongly suggest you replace the o-ring with a 112 urethane one before you attempt any modifications to valve seat or poppet valve to see if that solves your problem. The one shown appears to be very questionable.

The original valve seats appear to be flat or nearly so.
Click to expand...
Do you have a source of supply for the 112 Urethane seals for the 150 valve?
 
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if you go to a place like the Oring Store the rings are priced very well but the shipping kills that
there are the Oring you need and yes per Oring are pricey but it is part of the game we must play
https://www.ebay.com/itm/3615570186...KP8CpGOp8RPxtZHBQAzWnPa74rf2|tkp:BFBM9MWuxc1i

i am all about Urethane Orings when dealing with CO2 but i am not sure that CO2 would touch this Oring and cause it to swell through absorbsion
would i use Urethane, every time i could
the seal on the stem needs to be replaced there a i Mac1 video that shows him rebuild a stem
this sort of stem seal is very similar to the S&W 78g
they have to be pressed or other apart and R&R
 
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I too prefer polyurethane for use with CO2, but the more common Buna-N is perfectly fine for static seals like the one on the valve.

i am 100% with you after spending much time on the 850 forum polyurethane Orings are a must if you are do it right but granted harder to find
this video i watched yesterday show you some but what he is doing in the end i'm not sure
https://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/cr150vareki.htm
 
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