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Discussion Starter #1
I was putting my rear sight back on and I guess during the reinstallation the metal tab that holds the rear sight leaf spring cracked and is pushed up. now my rear sight has no tension.

Is this something I can fix with jb weld, or actual welding or does the entire trunnion need replaced? I mean I want to do the best thing for the rifle and the long term, it's such a thin piece of metal there.


you can see the metal cracked and pushed up at the base of the rear sight spring, it looks like a finger nail.
 

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That is the rear sight block, not the trunnion. To replace it you would have to remove the FSB, GB, LHR and the RSB. Then replace in reverse order. A good opportunity to fix any cant issues or de ban it if it was a thumbhole gun. Would require a press, some special press plates and a little elbow grease.
 

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You could try to have the re-welded., a chance it will be OK. A good welder might be able to put a brass filler behind the pulled up portion to keep the spring slot open and then but a weld bead in place to hold the spring or just weld the spring in place.
You can remove the barrel components without removing the barrel but a press is required.
 

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How about merely drilling a hole through that dimple in the leaf spring and tack-welding it in place?
Drill that hole and thread the sight block for a "small" machine screw.
 

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How about pulling out the leaf spring and dressing the buggered end with a file for a snug fit into the RSB slot and then re-bend an outward bow into the sight leaf spring. Here is a link with a pic of what the leaf should look like if its not buggered up. When installing the leaf in the RSB, put dimpled end into slot in RSB first and then lay the other end down into the RSB housing with leaf bowed outwards. You will need a drill press or other means to compress the leaf spring down further into the RSB housing until it clears the holes in the RSB enough for the sight ears to be installed. When applying pressure to the sight leaf, apply pressure at the center of the outward bow and compress the leaf only enough to allow the sight to be inserted into the RSB.

AK rifle rear sight leaf spring
 

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How about pulling out the leaf spring and dressing the buggered end with a file for a snug fit into the RSB slot and then re-bend an outward bow into the sight leaf spring. Here is a link with a pic of what the leaf should look like if its not buggered up. When installing the leaf in the RSB, put dimpled end into slot in RSB first and then lay the other end down into the RSB housing with leaf bowed outwards. You will need a drill press or other means to compress the leaf spring down further into the RSB housing until it clears the holes in the RSB enough for the sight ears to be installed. When applying pressure to the sight leaf, apply pressure at the center of the outward bow and compress the leaf only enough to allow the sight to be inserted into the RSB.

AK rifle rear sight leaf spring
The RSB is damaged. The retaining inlet in the RSB is bent and broken loose and is not retaining the spring. It is not about the spring.
 

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Discussion Starter #9
I think I will try to do the set screw thing. I mean the RSB is already screwed up so if It doesn't work I'm not any worse off than I am right now.
 

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OP...You DO NOT have to pull the barrel to replace the RSB. Get one of the Robert Forbus barrel de-populating tools and a shop press and you could probably have it done within an hour. The tooling catches the RSB around the ring that holds it to the barrel and allows it to be pressed off quite easily. The same tool also has the notches to remove the FSB and GB. I've used the version for chinese rifles and haven't even damaged the bluing when removing barrel parts.
 

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That was my thought as well. Welding the spring may get it too hot and ruin it.
Yeah, you guys are right. The heat on the spring didn't occur to me.

OP- unless that is a very, very special rifle I would just find a way to affix the leaf spring in the approximate place. Small machine screw sounds workable. You will never have any reason to remove it anyway. Pulling the barrel components off to replace the RSB would be most correct, but also ridiculous.
 

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You may be able to get a few threads tapped into that lower shelf on the RSB. Be sure you remove any protrusion on whatever screw you use or it will impede and contact the bolt carrier. Good luck., I would go with a weld bead to replace the upper material with a brass backer in place to save the insertion slot vs the spring as the welding is done. But whatever works for you. Good Luck.
 

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Discussion Starter #13
Thanks for all the advice guys! I got it fixed today. I used an 8-32nd carbon steel tap and threaded the hole where the rear sight leaf spring detent sits.
I broke the ledge off clear and refinished with birchwood casey super black touch up pen.

I drilled the rear sight leaf spring with a #29 drill bit, I also threaded the hole in the leaf spring with the 8-32nd tap.

I used a small flat head machine screw which was pretty close to the size I needed I just had to cut a few threads off the bottom with a rotary tool.

It seems to be holding very snug and I used red loctite on the threads. After I refinished the screw head and all the scratch marks with birchwood casey super black it actually almost looks factory now. Even the flat head screw looks similar to the grip screw and the hardware screws in the buttstock.

I'll take it to the range and make sure it doesn't go flying off under recoil and heat but it looks like this is a solid repair and much easier than replacing the RSB.

SPECIAL THANKS TO OMEGA7.62 AND AKBLUE for the tips, once I got all the parts and tools in place it really only took me all of 10 minutes to fix it.



 
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