Sunday, September 22, 2013

Crosman 101 reseal

Related Blogs:
Crosman 101 Disassembly

The valve in the 101 works the same way as the valve in the late model Crosman multi stroke pneumatic air guns, everything is just larger and less refined. 

I have the valve cleaned up and ready to be resealed. I purchased a reseal kit from Dennis Baker of Airgun Repair. The pump seal is at the top. The thick O-ring wont be used, some models had a groove for an O-ring to seal the valve body to the pump tube and this rifle doesn't have that groove. There were two check valve seals in this kit, I'm not sure if they all come with two or if it was a mistake. The thinner O-ring is to seal the exhaust valve to the body. A small tube of Pellgun oil is included in the kit.

The check valve unscrews so that the seal can be replaced. 

The seal was shot.


The exhaust valve doesn't look bad but I won't know for sure until I reassemble everything and test it. There were two styles of exhaust valve, the one pictured here and there was also a cone shaped (conical) seal. My other two 100 series air guns had the conical seal.

This is a picture of the valve from my 100 with its conical exhaust valve. There are a couple other differences, the spring is different and most of this valve is brass where the valve in my current project has some aluminum components mixed in. 

I laid out the parts to give a better idea of how everything works.
The brass valve body fits inside the pump tube, the pump tube is threaded and screws into the receiver. The aluminum exhaust valve seals against the brass body and is held in place by the nut that screws into the receiver.

The hammer assembly slips over the exhaust valve and the nut threads on to the end of the exhaust valve, the hammer spring is compressed against the nut when the cocking knob is pulled back. 

The face of the hammer assembly engages the sear and it is ready to fire. Clear as mud? Once you tear one apart it is pretty easy to understand how everything works.

It took a while to get all the old paint stripped off, I can see why people leave the brass exposed on their old Benjamins.... So Shiny!

Once the metal was all repainted and assembled, it is time to put the valve in. There is a paper/ fiber gasket that seals the valve to the pump tube. The gasket was showing its age and crumbled so I replaced it with a low tech replacement..... 

 Dental floss. I used this on my first 101 rebuild and it is still working.

Three or four wraps then push it up against the shoulder. 

Before installing the valve I applied some Crosman Pellgun oil to the floss the oil will soak into the floss and help seal it.

I used the exhaust valve and nut to install the valve body in the tube, tightening the nut until the body was seated.

With the valve body installed the check valve, spring guide and spring were dropped into the valve.

The exhaust valve was installed next, making sure it was lined up with the spring. 

There is an O-ring to seal the exhaust valve to the valve body.



Making sure the transfer port is oriented correctly  the exhaust valve is installed.

I used a drill bit to keep the transfer port oriented with the barrel and keep the exhaust valve from turning while the nut that holds the exhaust valve is tightened.


With the exhaust valve installed, the hammer assembly is next. The tube, spring and nut go on.


The cocking knob goes on last. The bolt needs to be installed before the knob. 

I left the trigger spring and guard off for the reassembly of the valve and hammer otherwise the sear gets in the way and could be damaged. With the valve and hammer installed the spring and guard can be re-installed


With the valve and hammer installed it was time to adjust the pump length. 

Since I was going to be removing the pump several times to get the length adjusted I used a 3/16" drill bit for the linkage to pivot on. 

I stopped here, the end of the pump is hitting the valve at this point. With a little more pressure the pump handle closes tight against the pump tube and stays in place. Zero dead space between the pump and valve is what I was going for. Once I was satisfied with the pump adjustment I pulled out the pump assembly and tightened the jamb nuts to lock everything in place.

With the pump linkage adjusted and everything tightened down I installed the pivot pin, notice the recess in the pin and the dimple in the spring clip.These need to be oriented correctly to hold the pin in place.The paint got dinged up during assembly, if I had let the paint cure before assembling it there would have been less damage. I'll have to do some touch up to the paint once I'm sure it is ready for final assembly.

Everything is working great so far, it pumps up and fires. On this rifle there is enough spring pressure on the hammer spring to hold the exhaust valve open, so the hammer needs to be cocked before pumping up the rifle, otherwise the air goes straight out the barrel with each pump stroke. 
I did notice an air leak, I could feel a puff air on my forehead every time I fired the gun. I put a barrel cleaning patch on top of the bolt and fired it to verify what I suspected, and sure enough the patch was blown off the bolt, verifying that it was leaking between the bolt and the breech. During the initial tear down the breach got dinged up while removing the barrel from the receiver. I had cleaned up the breech in the lathe and thought I had a good fit between the bolt and breech, it needed a little more work to get a good seal. To fix this leak I applied some automotive valve grinding compound on the face of the bolt, installed the bolt and rotated the bolt back and forth against the breech to lap the bolt to the breech. Lapping the bolt cured the leak and everything is coming together now. 

UPDATE:
I shot a string across the Chrony tonight, a 10 shot string with 14.3 grain Crosman Premier Hollow Points gave some great results. With four pumps for each shot I was getting an average of 475 fps. The impressive thing is the extreme spread was 5.4 fps and the standard deviation was 1.73 fps. Great numbers from an old air gun. Six pumps gives 550 fps and eight pumps gives 600 fps, again good velocities for an old pumper.  
I'm not getting the accuracy I was hoping for. My first groups looked like shot gun patterns, I was checking the crown and noticed paint inside the muzzle. I had plugged the barrel with a pellet before I painted it but some paint still got into the bore. With the paint cleaned out and another barrel cleaning the groups got better but still over an inch at 10 yards, good enough for shooting cans but not what I was hoping for. I'm going to spend more time with it before I do anything drastic....



























37 comments:

  1. Just come across your blog and i love the way you put it together, so well explained and easy to understand. You don't come across many old Benjies in the UK, but i found it useful and rellevent to some projects i myself have been working on.

    Brass barrels can be damaged so much easier in careless hands and that is an old one you have there, prehaps it was not loved as much as you care for it. Keep up the good work.

    TTFN

    Sir Nigel Tetlington-Smythe

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    1. Thanks for the kind words Sir Nigel. I'm glad you found some useful information.

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    2. Do you do these for a fee
      Thanks
      Richard Dean
      765 617 8408
      rid1946@aol.com

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    3. Richard I only repair my own airguns. It's a hobby and I don't want to turn it into job. There are a few guys out there who repair vintage air guns, a search online should find someone who can help you out.
      Thanks,
      Rick

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  2. Sorry it's a Crosman isn't it, just got up and haven't finish my cup of tea yet. Well that's my excuse.

    All the best,

    Sir Nigel

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    1. No worries, I'm on my third cup of coffee and still not fully awake.

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  3. I just received a 1927 101 it will need a new valve and piston (Im guessing) sinceits not holding air and the pump stroke offers no resistance. I was told it was the easier pumpers to reseal? Where would I purchase a new valve replacement kit and guessing piston replacement also. The hammer seems to work fine. Is there a special tool required to do anything in the repair process? Thanks

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    1. Did you have the hammer cocked when you were pumping? The hammer spring holds the exhaust valve open when it's released so cocking it before you pump it up is required.
      These old pumpers aren't as easy to repair as the newer ones in my opinion. To replace the pump seal you need a press to get the old one off and to install the new one. The exhaust valves can be stubborn to get out of the receiver and are easy to damage. I'm not trying to scare you away from doing your own repairs, just be aware that they can be difficult and require some patients. Dennis Baker is who I use to get my parts from. If my link doesn't work just google "Dennis Baker Airgun Repair" Good Luck and have fun, these are some great old airguns.
      https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAA&url=https%3A%2F%2Fwww.bakerairguns.com%2F&ei=Wi6VVZ6VDdDmoATYrK-YBg&usg=AFQjCNGznQfPN7mbql0mccmeLN_Y49yhPQ&sig2=hTWVfPnzjdSrc6_BgUrGtw&bvm=bv.96952980,d.aWw

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  4. Yeah, I tried cocking it first no no avail. Im just not getting any resistance when pumping and Im unable to hear any air either on the pump strokes. Almost like there is no piston cup? I dont know if I can check if piston cup is attached or not? There is a nut at base of piston and a nut near pivot point that spin and it cou)d be possible maybe to see if poston cup is attached by shortening the length (maybe) I just dont know whicj way to turn the nuts so something does not fall off?

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  5. In fact by by looking through the small air hole it looks like the pump cup is not attached at all. By looking at your pic of the piston rod I can only see a brass rod where the cup should be. The other piston parts are there just like your pic but no pump cap at end. I dont feel resistance at return pump stroke so there is dead space.

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    Replies
    1. The pump is easy to disassemble. The pin that the pump linkage pivots on (near the muzzle end of the pump tube) needs to be removed then the pump linkage slides out of the pump tube.

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  6. That sounds like something I could do. Have you ever heard of the pump cup coming off? That would explain why there is no pressure when pumping. At least, I would think. Good luck usually does not fall in my court. But, could it be "possible" that if I can fish that broken pump cup and put on a new one. That could be all it takes go get it shooting again?? Is it also possible that the pump cup came unscrewed (I dont know how the 101s hold the cup on)

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    1. It is possible that the pump cup came off and is still inside the pump tube, more likely someone tried to repair it and gave up. Most of the pump cups are pressed on but I had one that was held on by a nut.

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  7. Hello Rick
    My name is Rick also,
    I live in Plymouth Ma. I just came across a very old Crosman 102 repeater.
    It is in absolutely beautiful shape it has walnut checkered stock & forearm with the knurled cocking knob.
    This one doesn't compress air either, I did try it with the rifle cocked as stated above. I know not to go over 4 pumps as stated in the manual.
    This one appears to have 2 felt cups whereas yours has one however mine doesn't have the white cup on the end of your pump. Is this normal?
    Do you fix these for a price if so what do you think a ball park price cost would be to do to my 102 what you did to this 101 ?
    Sincerely.
    Rick

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    Replies
    1. I was able to see the pics. Great looking rifle! The white cup you see is a replacement, they are normally black. I don't do repairs, in fact I haven't done anything with airguns for a couple years now. You could try Googleing "Dennis Baker Airgun Repair" I bought my parts from him and he repairs air guns. Good luck with your project, those old Crosmans are my favorites.

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    2. BTW if I remember right you are better off calling Dennis, he is old school.

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    3. Thank you very much Rick !

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    4. This comment has been removed by the author.

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    5. I wish I did call Dennis.
      i went, with this other guy someone recoomended highly to me7 Thinking itm ight have been a mistake

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  8. Here are a couple pictures I hope they work
    http://i.imgur.com/qRPumHl.jpg
    [img]http://i.imgur.com/ZFHn3fP.jpg[/img]

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  9. Hey Rick I sent my Crosman 102 out to get fixed and for some reason the guy who repaired it replaced all the internals inside the rifle including the pump plunger that was in very good shape.
    I was under the impresion it only needed new seals I asked him to please send me the stuff back with the rifle itself.
    His rely was... "I tossed it all in the trash" why is it I find this so very hard to believe. I know for a fact these internals are very much sought after in the airgun community. This particular 102 was made in 1930 Mt grand father bought it new gave it to my father I want to keep it repectabl with this man but my patience are wearing this.

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    Replies
    1. I hope this story has a happy ending. It would suck to have something with so much sentimental value not be treated with the respect it deserves. Good Luck.

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  10. Mr. Rick,

    Thanks for all the hard work to publish the information on the Crosman 101. I received one in very good condition in yesterday's mail. I'm no stranger to working on air rifles. But it is always nice to have an idea what to look for when you open a new model up for the first time. With your information so clearly detailed, I am sure I can get the old girl working in no time.

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    Replies
    1. Thanks for the kind words. Have fun with your new project!

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  11. I’m looking at a102 repeater. Anyone know about tear down or rebuilding it and the repeater part too
    My email is 4jimcardinal@comcast.net
    I’m in Pa. thanks

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  12. i just aquired a crossman 104 its a 177cal. repeater in my reasearch is the rarest crossman there is it was only made for a few months at the end of 1949 the seals are toast i jury rigged some seals to get it to shoot so now im waiting for a seal kit this gun will be restored completely with a good powdercoat paintjob and wood refinish im glad to hear the completed specs for it when done thank

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    1. Congratulations on the 104, These old Crosmans are fun to restore. Glad you found some useful info.

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  13. Howdy Rick. I stumbled across a 101 and I'm currently stripping/detailing every part. I plan on resealing it soon, but before that I have one question. How did you separate the barrel and compression tube from the receiver?

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    1. The first thing I try is with the receiver clamped in a vice or to the top of my bench I put a screwdriver through the holes for the pump pivot pin. Use the screwdriver as a handle to unscrew the pump tube from the receiver. I had a couple that were stubborn and didn't want to unscrew and required more work. Try a good penetrating oil and if all else fails warm the receiver with a hairdryer or carefully with a torch. Go slow, you don't want to damage the pump tube. I had one that I let sit over night with penetrating oil on it and ended up using heat to finally get it to break loose. Good luck with your rebuild!
      One last thought is if you can find a wooden dowel that fits snug inside the pump tube, that would help to keep it from collapsing if it is really stubborn.

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  14. Thanx for the quick reply. I'm excited to get this classic launching pellets. Lastly, is there a trick to removing the barrel. Mine is brass,by the way. I'm not sure what year it was manufactured.

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    1. I start at the muzzle, take the pump pivot block / front sight off. Then loosen the screw that holds the barrel band at the end of the receiver. There is a set screw in the receiver just forward of the bolt that holds the barrel in place, remove it and the barrel can be removed. If I remember right I had a barrel that had glued itself into the receiver with corrosion, so penetrating oil and maybe some heat might be needed to get the barrel out of the receiver.

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    2. Great! I appreciate your info. ☺️

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  15. Howdy! Sorry to bug you again, but could you share any info on replacing the pump cup on the 101? I'm assuming the brass cylinder containing the felt wiper and the cup unscrews from the rod, but I don't want to force anything without being 100% sure. Thanx! ☺️

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