GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: stock600 on January 27, 2012, 11:52:55 AM
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I ran the serial number and dated my old .20 cal sheridan back to 1984, I bought it new many years ago and its not shooting hard as it used to. I found a kit online and purchased it, now ready for dissassembley and clean up. I'm having problems finding any info about it here or online, I'd like to be a bit more familur with it before I tear into it. I just finished not long ago tuning 2 benji's xl's and after reading here learning how and what parts to use it went very well. Just wondering if anyone wants to share any info on this model rifle or has a good web site that Ive not been able to find thus far? Thanks
Ryan
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Try this...http://www.network54.com/Forum/275684/message/1177168737/sheridan+C9+rebuild (http://www.network54.com/Forum/275684/message/1177168737/sheridan+C9+rebuild)
pv
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there is a special tool for getting the valve out of these.They run 10 - 20 bucks depending in where you get it from.Bryan and asc sells them pretty cheap.They work well.Did the kit you got have a lead gasket or was it other material?The lead is the best for sealing the valve.You need any help give me a shout as i have done one recently and i believe i took pics along the way.
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Thank you very much for that link. Ryan
Try this...http://www.network54.com/Forum/275684/message/1177168737/sheridan+C9+rebuild (http://www.network54.com/Forum/275684/message/1177168737/sheridan+C9+rebuild)
pv
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Hey that sounds great, Id enjoy seeing a few pic's if you have them handy. My e-mail is rntucker76@yahoo.com if you dont mind; or post them here? I plan to go through the gun this evening so we'll see how it goes, thanks again to both you guys. Ryan
there is a special tool for getting the valve out of these.They run 10 - 20 bucks depending in where you get it from.Bryan and asc sells them pretty cheap.They work well.Did the kit you got have a lead gasket or was it other material?The lead is the best for sealing the valve.You need any help give me a shout as i have done one recently and i believe i took pics along the way.
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The biggest problem you will have with currently available spares is the Intake valve will normally be inadequately crimped. The forming of the Intake (check valve) brass cup that holds the seal has had the final crimping process eliminated. This means unless your check valve or kit came from Mac1 or JG Airguns the Intake valve Crosman supplies will fail in a very routine fashion as soon as you push it.
Without the final crimp process the seal has no chance of keeping the high pressure from getting behind the seal and pushing it out of the brass cup.
JG sends me his Check valves and I reform them for him and everyone elses kits I've seen come without the Intake valve being finished.
When these guns come in is is obvious the user did the work himself and someone made money selling valve tools and parts that won't last.
I think I have around 11 tools dedicated to the Dan/Benj Rebuild process. Many my Grandfather made. One in particular makes the set which is the Tap to clean the lead out of the valve nut threads. According to my Grandfather if you don't have that tool you got no business inside of a Dan or Benjy. The threads should be cleaned out every time or you risk damaging a classic. The design concept forces lead into the threads to hold the valve in so you can put the nut on.
When you use the single tool you are lucky to get things in there and are even luckier if there isn't lead in the threads keeping the nut from tightening.
You can spend anywhere from $42 to $142 and believe me you get what you pay for. If your buying a kit make sure it is one with a fixed(fully crimped) Intake. Otherwise you're just exercising your wallet.
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Thank you sir for the advise. I will now pay close attention to this while in the gun, work has been so busy that Ive yet to get in her. Funny thing is the gun quit shooting many years ago and I put it up [~25 years maybe] I got it out here a month or so ago and the same thing it just wouldnt pump up. I ordered this kit and the sheridan tool from Bryran@ Associates; wierd thing is when I got ready to work on it I stepped out and tried it again this time it started pumping up pressure and sounds normal [ what I can remember anyway] when fired. I fired some rounds over the cronograph at diff. pumps to have a baseline after I finish my overhaul to see if thiers an improvment. Basicly it averaged:
563fps with 6 pumps
581fps with 8 "
582fps with 9 "
593fps with 10 "
I assume 10 pumps is the most you'd want to pump these is that correct? Thats just what I remember my father telling me as a kid. Fastest shot was a 623fps and oddly enough that was the first shot at only 8 pumps. What caused this great gun to stop working for so many years as a kid IS what I want to fiqure out. I got it new and it seems like I only remember shooting 3 of the old yellow plastic boxes of .20 cal pellets through it, so at maybe 1500 shots the ol gun should be far from worn out. Hopefully I can get into it pretty soon and I'll share what I find. Thanks again.
Ryan
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Original problem could have been a bit of trash on the valve seat. If you lubed it before trying it the fresh oil may have loosened the trash, blew it out and allowed it to seal. While it should be re-sealed (with the correct intake valve that Tim recommends!) it should be in top mechanical condition with that little prior use. Lube the 3 pivot points in the pump mechanism well! That's where the gun needs the greatest attention and old oil gets gummy. Use Crosman Pellgun oil, Tim's special pumper lube or NON-DETERGENT 30 wt. motor oil, air-tool oil or ATF. Just do it regularly---like a single drop on each pivot point every box of pellets you shoot.
Velocity makes me think that it's been left cocked a long time and the hammer spring is tired. More likely the hammer, spring and hammer chamber are coated with old, sticky lube. Replace the hammer spring and clean the entire hammer system religiously.
8 pumps is the max recommended. In good order it should be shooting between 650-700. 3-4 pumps works great for plinking. Most seem most accurate in my own experience at 5 or 6.
If a better small game rifle has ever been made it has escaped my attention and I've been at it almost 70 years! Tom
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Great post and thanks! You know Ive still not been into it yet, it's shooting great right now and super accurate. I have all the parts and the tool but going to shoot it a while before the tear down and inspection/overhaul. Ive been plinking a lot with my new Benji xl1500 and really like it but there's just something about my first air rifle thats special, you can really tell that these old Sheridan's are top quality. I agree it must have got a bit of trash in the valve because it just shoots to good now again with doing nothing but oiling the piviot points like you mentioned. I'll still find this thread and update on it when I feel like overhauling it, thanks again.
Ryan