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All Springer/NP/PCP Air Gun Discussion General => Vintage Air Gun Gate => Topic started by: Linkss56 on September 08, 2021, 12:33:15 AM
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Hey everyone it's been quite awhile since I've been on the site. I am having troubles with my crosman 140 3rd variant. I can't even begin to explain how many tins of pellets Ive put through this thing. I've been shooting this on a pretty consistent basis for well over 20 years, I've always kept it well oiled and stored it in my safe with a couple pumps in it safety on. All of the sudden it won't let me store multiple pumps in it and it won't self cock, I think it's not letting air from the pump chamber into the holding chamber. I'm not sure how these are constructed specifically because I've never had an issue with it but I have other rifles and understand the concept. Any ideas? Thanks.
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Don't know the solution but the cause was probably leaving it pumped, not a good idea with self cocking guns because well then it's always cocked.
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I understand it's cocked but it's never had anything done to it since it was purchased new by my father and that's how he stored it so the cup would stay expanded out against the pump housing, and not loaded of course safety on and locked in the safe. It's not letting me even store the first pump of air essentially, I don't have a manual and the ones online I can't read because of the quality, so I'm not sure what the mechanism is actually like but it has to have a one way valve that lets the air from each pump stroke into a chamber that stores 10 pumps. That one way valve must be stuck or something finally broke. I'll figure it out by tearing it down but I was hoping someone who knew more right off the bat would have a more detailed explanation of what is going on. If storing it wrong for 50 plus years has caused this malfunction and it needs gone through, I can live with that. Thanks again.
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Something is stuck, either the check valve or exhaust cap. It might break loose if you get a little alcohol in there. Many here have had success with this, I'm sure someone will guide you through it.
The first pumper I ever resealed was a 140. It was so gummed up with old oil, the bolt would hardly move. I got it apart and cleaned up, reassembled and it still shoots very well, with the pump cup that was in it.
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Hey everyone it's been quite awhile since I've been on the site. I am having troubles with my crosman 140 3rd variant. I can't even begin to explain how many tins of pellets Ive put through this thing. I've been shooting this on a pretty consistent basis for well over 20 years, I've always kept it well oiled and stored it in my safe with a couple pumps in it safety on. All of the sudden it won't let me store multiple pumps in it and it won't self cock, I think it's not letting air from the pump chamber into the holding chamber. I'm not sure how these are constructed specifically because I've never had an issue with it but I have other rifles and understand the concept. Any ideas? Thanks.
I'd do an alcohol flush and see if that clears it up. If it worked, them some secret sauce would be a good thing.
Luck,
J~
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Where do I introduce the alcohol? Leave the piston up and pour in it shake it around maybe let it sit for awhile then dump it back out?
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Where do I introduce the alcohol? Leave the piston up and pour in it shake it around maybe let it sit for awhile then dump it back out?
Here's a link to the video on it. I thought that you might do a search here about it.
https://www.youtube.com/watch?v=7WtGY17qltg (https://www.youtube.com/watch?v=7WtGY17qltg)
Luck,
J~
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Try the alcohol flush first. If it’s not cocking could be the quad seal in the valve cap is bad. It should set back slightly on the first or second pump. On my guns you can hear a soft click when it cocks. Resealing a 140 is not hard. Replacing the quad seal is probably the hardest part. Good reseal kits are available from Precision Pellet, Baker Airguns, and Mac1 Airguns. I’ve used them all with good results
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I appreciate it is there a video or tutorial on pressing the piston apart? I also have a 4th variant I picked up that has been in pieces for years, I had a kit but I have no idea where it's at when I was younger I didn't have the proper equipment to do it without destroying it so I just set it on the back burner after 20 plus years it's time to get it back together and I have a machine shop at my disposal now. I know I could do it but it's always nice to hear how others do it successfully. Also I have a 312 Benjamin how many pumps is it supposed to hold? Is it supposed to dump all the air for one shot? Mine you can shoot multiple times without having to re pump. Just curious I did a search but couldn't seem to find a manual or information about the amount of pumps. Thanks guys, I was in the Army for years, so it's good to finally have the time to get some of this stuff straightend out. I really appreciate it.
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Google ol’ Tomcats Crosman 1400 videos. It’s the same piston and valve as the 140. If you have a shop vise, a hammer and a drift you can replace the parachute seal on the piston. You will need to make a tool out of a thin flat piece of steel or a washer with a slot cut into it. Pry the parachute seal up a bit and slip your slotted washer under it. Then rest the washer on the partially open jaws of a vise. Use a hammer and drift to drive the brass bushing off of the piston. Then you can install a new parachute seal and tap the brass bushing back on to hold it. Mac1 airguns sells an O ring piston head that is simpler to install than the OEM parachute seal and works about as well. The O rings are easily replaceable if needed but the gun requires careful pumping with the O ring piston head. Pumped too briskly and it will burp air at the end of the stroke. Once you learn the pumping technique required it works as well as the factory seal.
If your Benji is retaining air you are probably over pumping it. Eight pumps ought to be enough.
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If you need to replace the quad seal, I use an Exacto razor blade for removal. Than just squeeze the new one back into the cap.
Be careful fingers will bleed if you slip.
Feel free to PM me if you have any questions.
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Okay thanks for the information, is the old parachute seal available from anyone? Do you guys run Viton seals or any special kind of seals? I've always just used plain old black orings from the kits. That's how I bought the 312 once again years ago, it's amazing how long these will hold pressure, I ran a few thru it and thought something wasn't right and put it away. Of course there was no internet back then so it wasn't as easy to exchange knowledge on everything.
So I put alcohol in both the 140 and 312. The 140 immediately clicked after I closed the pump lever so that's a good sign and the 312 also clicked but it was alot louder and clanky kind of noise so I'll just let them soak and see what tomorrow brings. So I'll just keep firing the 312 until all the air is exhausted and then give her 8 pumps. One small off topic question, what is a PRod? I've seen some pretty cool builds on here and mods. The site has really come along way since the last time I was on here. Thanks again.
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PRod = Benjamin Marauder pistol.
Oh yeah Baker airguns has the factory parachute seal.
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Prod is basically a 2240 with all the mod parts that builders used to do to run their 2240s etc on HPA. The Prod has a 300 psi max fill, but runs better with a 2700 psi fill, and we are still modding them to make us happy :)
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Viton or some sort of special seals? What's the best?
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Viton or some sort of special seals? What's the best?
I believe most plain old black o-rings will work in a pneumatic. Viton or Buna. I prefer Urethane or Buna in a CO2 gun. Not all seals in the 140 are o-rings, the valve cap has a squarish quad seal.
Is your 140 working now? Be sure to give it some oil after the alcohol is all out.
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If and when you decide to re-seal your 140, take the time to view some videos and download the Crosman exploded view diagram to get familiar with the parts. They are pretty straight forward, but a few tips, like the one shared on the parachute pump cup helps. I cut the old cup totally out, and that leaves room for a washer, cut like a "C" to slip in to drive off the brass sleeve. They can be really hard to remove, and having everything lined up and secured when you pound on it helps.
When you take out the screw on the very end of the barrel, near the breech, note that there is a small retaining washer in there that must be removed first, to allow the rear barrel cap to slide out. Too many times folks just keep prying it with a screwdriver thinking it is stuck, and booger up the cap. Some inexpensive dental style picks are really handy for this hobby, especially that seal/washer, and the quad seal mentioned.
Perhaps the alcohol rinse will fix you up for now, but eventually, you may need to reseal it.
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Forgot to mention that on those 3rd variants, the safety needs to be removed before the stock. Point the safety lever straight down, and it should slide out with a little resistance. The stud that holds the stock on, also inserts in to the valve, holding it in place.
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Just a thought, I had a 130 pistol that would not pump up
Turns out the tip of the sear had broken off and it would not hold the sear block forward
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Hey everyone, the alcohol did the trick. I'll reseal it when the time comes. I appreciate all the help, and insight. It won't be a problem when the time comes and I could do it all on my own but many heads are better than one and it's nice to hear how and why people do it the way they do. Right now I'm building my 4th Girardoni from raw materials. Thanks so much again I may try putting together a PRod or some other Franken- setup.
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Congrats on getting your 140 going again using the alcohol flush! Sometimes just a little maintenance and oil are all they need!
I just finished restoring a second variant 140 this weekend, spoon handle, self-cocking. It had the numbers "96" stamped in the stock, so I'm presuming September 1956. It was from an estate sale, and it had never been apart. Re-sealed it, and got 554 fps on 6 pumps! Just saying if you do need to re-seal, they are pretty straight forward.
How about some pix of your Girandoni's you built? Fascinating rifle with a great history. If you can build one of those, you can certainly re-seal a Crosman!