Continuing with the testing of my old vintage airguns series, the Crosman SA6 which hadn’t been fired for a long time had a slow leak after being pressurized with CO2.
The SA6 is one of the model for which I didn’t have a service manual. The exploded diagram exists and good info can be found on the Web but I was a bit intimidated because the exploded views drawing showed that a jig was needed for reassembly.
Luckily I came across a post that mentioned that the jig was not necessary as long as the cylinder was sitting at the right level during reassembly. A few wood pieces wisely placed were sufficient.
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I tried to be careful to not remove more parts than I needed to access the valve/piercing assembly and even placed a pin through the hammer hole so that nothing else moved.
Multiple pictures were taken to ensure a good understanding of the parts’ relation.
What I discovered working with vintage airguns is that taking components apart can be sometime tricky and this is what happened with this valve.
On Another Airgun Blog site, the person used his lathe chuck to hold the valve body and placed a punch in the transfer port hole to unscrew and separate both parts. This didn’t work for me.
I tried heating up the parts and even made a compression block to hold it in my vise and a compression handle with a pin to have more leverage. Nothing was working because the part was still spinning in the compression block. Finally, the day after, I decided to try a last time by cutting my compression block completely in half and adding a layer of rubber. It worked and I was back in business to continue the repair.
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This stem seal/poppet is different than the ones I have seen before because it has two ends and one of them is pointy to pierce the CO2 cartridge. I made the shaft on the lathe and filed the end into a nice point then machined the Delrin for the seal but when I assembled it, I discovered that it was a bit too long.
I decided to use a different method to shorten the pointy tip. The stem was placed in a Dremel tool to spin it and the belt sander would remove the extra material. That was a bad idea because it went way too fast and I ended up with the shaft being too short. I am not sure if this is part of getting old but I discovered that I sometimes have to do things twice these days.
I looked at the seal for the CO2 cartridge and it seemed that it was not the regular type found on the Crosman airguns but it was not leaking and felt pliable so I decided to keep it. I slightly sanded it to remove some of the marks in the surface before reusing it.
The valve was reassembled but before putting everything back together, there was another thing that was annoying me. The Retaining Assembly for the CO2 cartridge was difficult to get finger tight enough to ensure a good seal and sufficient pressure to be pierced. It required the use of pliers which I didn’t like.
At first, I thought that a regular screw would do the job but after looking carefully how it worked, I discovered that the treaded shaft had a linear movement when the nut was turned. A screw would apply a rotational force on the CO2 cartridge and the spinning might damage the seal so that was not a good option.
I decided to keep the original retainer screw and replace the original retainer nut by a nut I machined from a hexagonal bar. I also drilled a small hole in each faces and made a small tool used for tightening the nut.
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To the exception of reinstalling the small indexing ball and tiny spring reassembling the pistol is not too bad. The SA6 is now fully functional.
R-Gun Pete