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Posted: 10/25/2004 6:44:42 AM EST
[Last Edit: 10/25/2004 6:46:10 AM EST by MadDog760]
I am needing another US part in one of my AK's and I have a US piston from Tapco. I can see the old pin as it is ground flush with the bolt carrier. How hard is it to replace the old piston with the new one? Any tips? Just drive the old pin out, screw in the new one, drill the hole and pin it in again? Do I need to order a new pin from K-Var?

TIA...MadDog(760)
Link Posted: 10/25/2004 12:23:09 PM EST
Easy as cake. If you can clearly see the outline of your current pin, wrap your carrier and put it in the vice. Pound the shit out of the pin with a good punch and drive it out. Unscrew the old piston and screw in the new one. The new one should not bottom out. Leave some threads showing so that the piston will have play in the carrier. When you have it screwed in the proper depth, drill a new hole and drive in a new rod.
Link Posted: 10/27/2004 4:34:00 AM EST
Since the pin is peened over, I drill into the end of the pin to remove the peened area before I punch it out. That way I don't have to pound the shit out of it.

You can use a nail as your new pin. Peen it over and grind flush.
Link Posted: 10/28/2004 10:10:39 AM EST
This is on a Chinese MAK 90. The pin diamater is larger than a nail. The pin is almost the size of a pencil...

Do I need to get another pin or use the old one?

Link Posted: 10/28/2004 2:33:42 PM EST
The pin looks that big because it has been peened out like Val mentioned. Drilling some on one end will make it easier...thanks for mentioning that Val. I think you could beat on it all day if you dont drill it.
Link Posted: 10/28/2004 2:55:56 PM EST
CENTER PUNCH then drill. The pin should be softer than the carrier and you should be able to "feel" it a little if you are cutting the carrier. So center punch small drill bit, then larger drill bit. Do it from both sides, you don't have to drill all the way through. then you shoudl be able to twist off the piston. I wouldn't say "easy as cake" but not impossible either. DEFINITLY need a drill press IMHO.
Link Posted: 10/28/2004 7:35:08 PM EST
[Last Edit: 10/30/2004 12:21:35 PM EST by AtlantaFireman]
On both my AMD-65 kits, the holes were VERY difficult to locate. The factory installation was near perfect. I used emory cloth to find the irregular spots on the bolt carrier; this is where the pin was. I center punched, then drilled with a larger than needed diameter cobalt bit on both sides, then punched out pin...it was no tea party. I then made my own gas piston using the original as a guide, and stamped USA on it after installation...like a dummy. OK, this was a pain in the [neck], but the lathe was fun. Polished it using emory cloth. Solid pinned, then welded a bead on the pin, ground down to match bolt carrier's shape, and refinished with Aluma-Hyde II, matte black. Matches perfectly.
Link Posted: 10/29/2004 4:04:11 PM EST
This information will be a big help.

had not seen the pin the 1st time I looked.


Thanks guys
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