Benjamin 312 and 132

Hey dudes I just ordered the baker seal kit for my dad's 132 and 312. I'm bringing them back to life for his birthday. I ordered the tool for them and I already found a video for the 312. I'm just wondering if you guys have any advice or secrets to make it easier on me. Also wondering if you guys know what size roll pin would fit in both. I have no idea how both of them lost thier pump lever pins but they did. Anyways I just wanted to say thank you guys for always being there to give me good advice. 
 
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Oh yeah the barrel is coming apart at the muzzle. Someone tried to solder it and did a poor job. I am going to try to silver solder it after all the internals are out of it. If you guys have any advice on that please let me know. I'm going to get some pipe at the store and practice until I'm confident. Also let me know if I should leave it looking old or polish the brass and restain the wood. I'm leaning towards just leaving it alone but let me know what you think. 
 
When I re-soldered my 310 barrel, I lightly ran a piece of about 220 wet or dry paper back and forth in the separated area to clean both barrel and tube. I wrapped a wet rag around the barrel and tube in the area of the valve as a heat sink, Used a good circuit board flux and applied it to the joint. I used soft solder as it does not require as much heat as silver solder will. Evenly heat the area both sides of barrel and tube and flow the solder into the joint. I actually flattened a piece of solder, put it between the barrel and tube. Used a piece of wire and wired the barrel and tube together and applied heat. When the solder melted the barrel and tube came together very nicely. Removed heat and let it cool. Got a got solder joint that is still holding.



Good luck and leave the finish as it is.