Reassembling the Smith and Wesson Model 78G Pistol

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whig

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Dec 21, 2022
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MARIETTA
Hi. I am new and signed up to see if the experts here can help me to find out where I can get information to reassemble my vintage Model 78G pistol that I disassembled, cleaned, repainted and replaced seals on. Now, I need to figure out reassembly. I hoped I could find a youtube video to help me out. I don't know how to even get the valve reassembled yet and don't want to damage anything.

Thank you for help.
 
Thanks for your kind reply. I had trouble with the valve assembly stem going through the front hole in the valve casing. It didn't push through. The back valve body plug is not pushing far enough into the casing for the cartridge connector to fit in because of this. But I found the problem. When I was disassembling it, the valve stem was stuck and I had to punch it out with a punch tool. This buggered up the hole a little and wouldn’t allow the valve stem to push through smoothly. I cleaned up the hole with a small round file and it is smooth and now lets the stem slide through it. I got it reassembled. Now, I need to reassemble the rest of it. Is the a video anywhere showing the details or is the Tom Gaylord link above the best instructions available? I may be able to follow the schematic in the manual I have to get everything back together now, hopefully. It's just the tricks that sometimes need to be followed to get some of it to work that I don't know. We'll see. Thanks. I still may need help!
 
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I haven't found any videos on it, but it is a pretty modular straight forward assembly. One trick which helps a lot is holding the trigger down firmly while putting the hammer back into the frame. Keep holding down the trigger so it the hammer stays down while you put the slide on. Then insert the metla tube in the front to lock the front down and the screw on the right rear that holds down the back.
 
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My main problem right now is getting the trigger spring in and seating the cocking lever engaged with the trigger. It just isn't fitting and working right. If I could see exactly how these parts are fit together, that would help. The schematic doesn't help me. The valve seems awfully tight but I didn't change the spring when I put the new valve in from the MAC1 seal kit I got. Thanks!
 
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Once you finally get the trigger spring in place, hold the trigger back with a wire tie around the frame. That way the hammer/cocking lever and hammer spring can be put in place comfortably. Pics in this link might help.

www.pyramydair.com

Smith & Wesson 78G and 79G target pistols: Part 4 | Pyramyd Air Gun Blog

B.B. blog post titled Smith & Wesson 78G and 79G target pistols: Part 4 explores new information, history, tips and tricks at Pyramyd Air.
www.pyramydair.com
 
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Well, it's all back together. Tying back the trigger is what I needed. A few small things I figured out. You really need some help in doing new projects like this the first time. I thought I had a couple cartridges but I don't, so, I need to get some to test it out. It cocks and fires correctly though. I do have the earlier one with the trigger adjustment screw. Is the Allen set screw on the top for tightening down the barrel? Thanks all! Merry Christmas.
 
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