[1950oldsoldier]

1. What is the best way to clean the gas piston??

2. What is the 'torque' pressure to reinstall after cleaning??

3. What kind of torque wrench would you use??

Jim

[Mooseman684]

1.Best way is to use a spray Brake cleaner or similar solvent. Compressed air will help too.
2. You should NEVER remove the gas Piston , the retainer is set and staked in place.
3. It takes a special Wrench to remove one and replace it .

[1950oldsoldier]

Thanks Mooseman, I was all set to take it apart and really clean it. Thanks so much for your advice
Jim

[oldjarhead]

I pretty much agree with Moose except for the first one. Use a brass brush to clean any carbon from the piston. If liquids seep into the chamber, carbon residue can be trapped (build-up) by the solvent and may end up clogging the gas port and subsequently the piston may stick; then you have no choice but to dismantle the gas system...or send it to Moose so he'll have work...lol

BTW, I've seen this happen and the little semi-auto shooter becomes a little single shot shooter.

[Mooseman684]

I've never had that problem using solvent to clean the piston ,chamber and gas port...FM23-7 Manual says to use Rifle Bore cleaner , or Mineral spirits for cleaning and removing Powder residue and to brush away carbon from the piston nut...then lightly lube it with oil.
I probably should not have said "Never" remove the gas piston nut because sometimes if it is not cleaned and it sticks , then it has to be done , but I should have said you want to avoid removing the nut as much as possible to avoid wear on the threads and risking damaging the nut by spreading the ears...as long as the piston slides freely...
Rich

[oldjarhead]

Quote:       Originally Posted by Mooseman684

I've never had that problem using solvent to clean the piston ,chamber and gas port...FM23-7 Manual says to use Rifle Bore cleaner , or Mineral spirits for cleaning and removing Powder residue and to brush away carbon from the piston nut...then lightly lube it with oil. I probably should not have said "Never" remove the gas piston nut because sometimes if it is not cleaned and it sticks , then it has to be done , but I should have said you want to avoid removing the nut as much as possible to avoid wear on the threads and risking damaging the nut by spreading the ears...as long as the piston slides freely... Rich

I try to avoid it as well. With the proper tool the nut is easily removed but for some reason (probably the stake point) the gas nut is difficult to get started into the threads. This can cause cross threading if you don't take your time...that pretty much results in a re-barreling job.
Sometimes it seems a simple project can get out of control real quick...lol

[Mooseman684]

Quote:       Originally Posted by oldjarhead

I try to avoid it as well. With the proper tool the nut is easily removed but for some reason (probably the stake point) the gas nut is difficult to get started into the threads. This can cause cross threading if you don't take your time...that pretty much results in a re-barreling job. Sometimes it seems a simple project can get out of control real quick...lol

Exactly !

Rich

[jimb2]

IF it does become necessary to remove the piston, the threads should be chased before the nut is put back in.. I have the necessary tools to do the job correctly, the original armorers tools. I recommend against removal. Soaking with a good solvent like brake cleaner will normally do the trick. The only time it should be removed is if lead bullets have been fired and the piston is leaded. That is rare as most carbines like cast bullets.

[1950oldsoldier]

Thanks guys, I am a Carbine user but maintenance like removeing gas piston, etc was above my pay grade. Thanks for the advice that kept me from screwing up.

Jim