G43 Frozen Gas Cylinder - Comments Needed

[robinson479]

Hello Kar98k members,

This is my first initial post on the site as I am just getting settled into the forum. First I would like to say I am a young collector who absolutely loves WWII weapons ever since I was a kid growing up. Recently, I purchased a G43 rifle and discovered as I was taking all the parts off, the gas cylinder would not move. YIKES. Did a quick Google search (like we all do) and found a gentlemen with the same problem. I thought cool, this will be fixed in no time. The members of the forum recommended 'Kroil', a penetrating oil to break up the rust and use a little bit of heat on the tube (not too hot). They said to soak the barrel (nose down in a bucket) in the oil for a while, then work it loose. Others recommended PB Blaster, WD-40 and the like.

Link to original post K98k forum: click here and Gunboards post here

Not an issue. I bought some Kroil and made myself a little gadget to soak the cylinder and gas piston in oil for a while since I couldn't figure out a way to soak the entire barrel in it. I started soaking in the middle of April. After looking at the gas cylinder for a while, I noticed a small divot, where it looks like someone tried to punch a hole through it. I quickly thought the divot was adding to the cylinder not being able to move. So, I e-mailed Rob Apfeltor AND Claus Espeholt for their opinions.

Here is what Rob Apfeltor said:

"That divot is where the two pieces of the cylinder are staked together. Definitely NOT the problem. You need real heat my friend, then work it loose." - Rob

And here is what Claus Espeholt said, initially:

"I think the divot is the problem. Can you remove it ? grind it off ? or drill it away ? It's a little pity to do such a thing with an original gas cylinder - but I think you have to do it. Best regards" - Claus

After a few e-mails back and forth, he too came to the same conclusion as Rob after I told him what he said about it. He concluded:

"I think the divot is so close to the “small end” that it can’t be the problem – but I can’t remember I have noticed it before! No I do not think the divot is the problem." - Claus

So, as Rob stated, I used Propane Gas to slightly heat the cylinder and attempt to work the tube loose. No luck. Did a rinse and repeat (soak in Kroil for a few days/week - heat the cylinder with Propane). No luck, yet. I am planning to try and re-heat the cylinder and give it another go tomorrow.

I've attached a few pictures of my Kroil setup that I will explain. I have the receiver and barrel out of the stock, upside down hanging from a piece of rope and sitting on a few wood blocks. I cut a lotion bottle and tied it to the top of the barrel so it would hang and hold the Kroil. I filled the cut lotion tube as much as I could without oil spilling over into the container. Almost the entire cylinder is covered. The barrel is hanging at a slight angle so the oil will run into the gas cylinder and around the gas piston. I have attached the picture of the setup and divot on the pi. It should be noted that when I apply heat to the tube, Kroil starts to come out of the divot, as well as both ends of the tube.

Do you guys have any other suggestions?

This is going to be my thread to track progress or seek help from experts here (if that's OK) until I get this thing off. I'm at the point where I just want the rifle back together and not in pieces! One thing I have to remember is patience is key..

 

[reich1900]

I suggest that you try Cabot' Tasgon the original penetrating rust solvent. A friend gave me a can of this stuff quite a few years ago and it's GREAT but smells Terrible. All you would need is a few drops and leave it for a few days OUTSIDE. If it still doesn't come loose then try it again until it does. It has never disappointed me. On my G43 I couldn't unscrew the piston and thought I would damage it with the tools so I used the solvent and forgot about it for awile. When I went back and tried to unscew it, it came undone like it was just a little more than hand tight.

IT WORKS but I have no idea where to buy it.
Bernie

 

[Tiger 2 Tank]

I'm only guessing on this, so keep that in mind. I don't think it's rust or corrosion, I think it's the "divit". I think the divit is dented between the gas cylinder's " ribs", hanging it up. I don't know how damage like that divit could be done as it looks like a direct punch occurred somehow. Again, just a guess.

 

[agalland]

I would suggest more heat...just a little heat doesnt do much...and with porpane only you most likely wont get it too hot..get it hot enough that water pops and sizzles when it hits it...but be sure and heat it as evenly as possible all around the base.,

I agree with Claus..I think the divot is too high to be impinging on the piston.

Speaking of Claus...when did he get out of prison..?

I suppose time has got by me and he has completed his sentence perhaps....I am thinking it was 5 years..?

Glad to hear he is out.

 

[ebeeby]

My 2 cents:
I don't think it's the divot because (my understanding) it doesn't move at all.

I also think that the tolerances are such that the Krol can't penetrate.

When Rob says "real heat" he means just that.

I had the reverse with a piston frozen solid to the gas block (I was installing a shooters kit). It required quite a lot of torch to break it loose. In that case I had a good wrench fitting of course. In this case, in order not to score the original cylinder, will require the sacrifice of some good latigo leather between the pliers and the cylinder. The cylinder should be hot enough that the leather nearly catches fire when applied. But with enough heat that should do the trick. Of course the barrel and gas block will have to be carefully secured so that the torque applied to the cylinder does not wrench the gas block.

 

[robinson479]

Thanks for all the initial responses, I'll try to respond one by one.

@reich1900 - Sounds like something I could try, only see that it may be sold on eBay, not sure where else. I'll poke around some more. In your experience has it altered the bluing of a gun in anyway? Not that it matters much to me on this cylinder. What do others think about this? Anyone else had experience?

@Tiger 2 Tank - Do you think if the divot was holding it on that the cylinder would be able to rotate clockwise or counter-clockwise around the piston? Meaning it can't be pulled straight back away from the gas block, but can still "spin" on top of the piston?

@ebeeby - What do you mean by the divot doesn't move at all? How would you recommend securing the barrel and gas block before torquing the cylinder? Maybe using wood boards with pressure clamps on a table?

@agalland & @ebeeby - I'm not sure how much "heat" you guys are talking about. I'm using a propane torch, lighting it up and placing it about 2-4 inches away from the tube. The left over Kroil in and around the tube starts catching fire and smoking (nothing too serious). I apply constant heat for about 20-30 seconds and then let it cool for another 30 seconds and repeat the process about 6 more times. I'm trying to install a shooters kit as well, but haven't purchased one since I haven't been successful in getting the cylinder off yet.

I haven't figured out a good method to attempt to work it loose yet either after heating it up. And I guess I will look into that leather and get some to apply to the tube after heating it.

Thanks for all the responses - I look forward to hearing more thoughts from all of you.

 

[agalland]

SOmetimes a few rounds will help bust it loose also...nothing like an explosive jet of hot gas slamming into the cylinder to help[ coax it off....but..before you do that make sure you install the new spring kit to absorb the punch should it break loose..

And eeby is right..real heat is the trick.

 

[Tiger 2 Tank]

In my senerio, it's possible and would depend on if the punched metal is between the ribs or not. The heating method and Kroil methods that are being offered, worked on systems that didn't have this punched area like yours does. If you shoot that rifle, and the punched area is hanging up the system, you might have bigger problems.

I just can't think what would have caused the punched divit?

 

[GunKraut]

The dimple is factory made. This gas cylinder resembles an early Type I which unlike the later cylinders is a two piece design consisting of a tubular pipe and an end plug for the connecting rod. The end plug usually has a cannelure like a bullet and after its installation, the cylinder is crimped where the cannelure is located, making for a solid, gas tight fit between pipe and end plug. Apparently, your gas cylinder only has a dimple instead of a crimp running all way around the circumference. I have one just like it and this joint comes loose easily. Needless to say, the early Type I was quickly replaced by the single piece interim Type II cylinder and the late Type III cylinder with the blow hole.

Your gas cylinder is frozen to the gas piston. You need to get it moving one way or another. You could try to get a couple hose clamps next to each other on the cylinder, tighten them securely and carefully tap against the clamp's worm gear to force the gas cylinder away from the gas block and off the piston. When it starts moving, tap it back in the opposite direction to work rust and carbon loose, then tap the worm gear again. Eventually the cylinder will free up and come off. As others already said, heat will greatly assist your efforts. In order to keep the worm gear from damaging the gas cylinder you should wrap a thin layer of sheet metal cut from a PBR can or a Campbell's soup can around the gas piston.

 

[armenjs]

Wow, small world when you have a G43. I had a similar issue with my gas cylinder. You are almost there. Kroil and heat it, like others said. I didnt have torch but heat gun will do( worked for me). You need a leverage, protect your gas block with leather or cloth and place 6'' crescent wrench on the gas block and 10'' on the cylinder. Have your buddy to hold the stock firm. Apply sizable force on the the 10'' wrench, apply force counter clock and fix the 6'' steady as you can. You will hear the parting sound soon. GL

 

[robinson479]

The dimple is factory made. This gas cylinder resembles an early Type I which unlike the later cylinders is a two piece design consisting of a tubular pipe and an end plug for the connecting rod. The end plug usually has a cannelure like a bullet and after its installation, the cylinder is crimped where the cannelure is located, making for a solid, gas tight fit between pipe and end plug. Apparently, your gas cylinder only has a dimple instead of a crimp running all way around the circumference. I have one just like it and this joint comes loose easily. Needless to say, the early Type I was quickly replaced by the single piece interim Type II cylinder and the late Type III cylinder with the blow hole.

Your gas cylinder is frozen to the gas piston. You need to get it moving one way or another. You could try to get a couple hose clamps next to each other on the cylinder, tighten them securely and carefully tap against the clamp's worm gear to force the gas cylinder away from the gas block and off the piston. When it starts moving, tap it back in the opposite direction to work rust and carbon loose, then tap the worm gear again. Eventually the cylinder will free up and come off. As others already said, heat will greatly assist your efforts. In order to keep the worm gear from damaging the gas cylinder you should wrap a thin layer of sheet metal cut from a PBR can or a Campbell's soup can around the gas piston.

First time I've heard anyone say this was factory made. The thought initially crossed my mind as I couldn't understand what this divot was trying to accomplish if placed there by someone else. It almost seems like the divot is there to act as a pressure release from all the gas coming up from the barrel and into the piston. Can you explain this 'end plug' piece a bit more? Do you have any pictures of it? If this is factory made, the entire cylinder would be able to move freely, back and forth, on top of the gas piston when the rifle is fired. Is that correct?

I'll try to get something set up for hose clamps and see if that does the trick.

@agalland - I've seen suggestions about shooting a few rounds through the rifle, but didn't want to risk breaking anything if I didn't know what the divot was doing to the cylinder. I'll have to get the shooter kit before I try this method, wanted it to be my last resort.

@armenjs - Will applying that much pressure to the cylinder to anything to damage the cylinder? I guess if you try to rotate it counter-clockwise or clockwise, it may break up the rust and corrosive between the piston and cylinder. I'll try this as well.

I've attached a picture of the different types of gas pistons for G43s and mine is most definitely the last one pictured.

 

[GunKraut]

I added a picture of my dimpled Type I gas cylinder to my previous post. The cylinder is just a piece of pipe. Please note there is no crimp or cannelure. The end plug is joint to the pipe by press fit and dimple only.

This video explains how the gas systems works:

 

[robinson479]

@GunKraut - Thanks for the response. If I'm understanding you correctly, the 'end plug' is the piece of metal that is between the dimple (divot) and the end of the cylinder (to the right in your picture). It is separated by a line where the plug was fitted onto the cylinder, if I am understanding. I'll have to find a picture of the crimp or cannelure to understand what you are talking about, not sure I've seen one (trying to familiarize myself).

I have watched the video on YouTube and actually e-mail the gentlemen first about my problem and he has said similar things that the community is stating here. His response:

"The frozen gas cylinder is fairly common. Try the Liquid Wrench/WD40/Kroil method first, use a piece of soft metal with a knife edge to wedge between gas piston and gas cylinder right where it screws into the gas block. Once it cracks open a bit, tap it back in the opposite direction and start all over. Eventually the internal rust will scrape off and you can tap the cylinder off of the piston.

Please let me know if this worked for you. Be patient. A heat gun helps a lot."

 

[GunKraut]

The end plug is crimped into the gas cylinder the same way a bullet is crimped into a brass cartridge. The analogy would be: gas cylinder pipe = brass cartridge, end plug = hollow point bullet.

Below is a link to a good website depicting serious damage to a Type I gas cylinder. You can clearly see how the pipe cracked where it surrounded the end plug. The end plug goes into the pipe almost as deep as the cracks are. When you look closely at the third picture you'll see the groove (=cannelure) in the end plug. The end of the pipe is then crimped into the groove to firmly join both pieces together. When it failed, almost the entire crimp broke off the pipe; you can still see a small remnant of the crimp on top.

http://apfeltor.com/html_pages/damage/cylinder/hobnailspage4.html

 

[Peter S]

If you look closely at Rob's picture you will see that the end plug is actually screwed into the tube. The cylinder that the OP shows has no crimp, only the dimple to keep it from unscrewing.

I have loosened them by using the shooting method. It's real fast & easy. BTW, you cannot install a shooters kit until the cylinder is free.

 

[robinson479]

If you look closely at Rob's picture you will see that the end plug is actually screwed into the tube. The cylinder that the OP shows has no crimp, only the dimple to keep it from unscrewing.

I have loosened them by using the shooting method. It's real fast & easy. BTW, you cannot install a shooters kit until the cylinder is free.

Thanks for the insight GunKraut and Peter.

@Peter - A lot of people have stated that, just wanted to make sure it was OK to shoot the rifle without a shooter's kit to break it free (I didn't know what the divot was at the time either). I know I need to get the cylinder off before I replace the gas piston. As @agalland stated earlier, I would probably want to get the replacement spring set from Rob Apfeltor before taking it to the range.

This is great info, thanks again.

 

[GunKraut]

If you look closely at Rob's picture you will see that the end plug is actually screwed into the tube.

I stand corrected. Apparently the end plug is screwed into the tube and not press fit as I assumed. This also explains the cracks: Due to internally threading the tube the wall thickness was reduced, leading to higher tensile stress in the threaded area which subsequently lead to accelerated material fatigue and premature failure.

Since the shooter kit consists of a piston and cylinder, the OP could use a brute force approach as a last resort option and remove the frozen cylinder and piston in one piece. But this option should be postponed until all other options have been exhausted, as it could result in the destruction of original, matching parts. I would use a 3" piece of thickwall steel pipe drilled or reamed out to the same diameter as the cylinder, cut a slot it in length wise, pry it open just a little bit, coat the outside of the gas cylinder with Comet cleanser for better grip and shove the pipe over it. Then grab the pipe with a couple vise grips and try to carefully unscrew the whole assembly 1/16 of a turn at a time.

 

[rpf2697]

I have had great success firing single rounds of ammuntion with the handguard removed in order to free up stuck gas cylinders. Bring a small wooden dowel and hammer to tap it back on in order to fire additional rounds since it usually only starts to free up in short segments.

 

[armenjs]

I stand corrected. I had similar issue with the cylinder and the piston. My post pertain to the piston (It can also freeze up). For Cylinder follow gunkraut or you may use tap method to slide off the cylinder. use small flat screwdriver or flat solid small enough to go in place and tap with mallet. Make sure you leave it in the kroil and heat it before starting.

 

[reich1900]

Thanks for all the initial responses, I'll try to respond one by one.

@reich1900 - Sounds like something I could try, only see that it may be sold on eBay, not sure where else. I'll poke around some more. In your experience has it altered the bluing of a gun in anyway? Not that it matters much to me on this cylinder. What do others think about this? Anyone else had experience?

@Tiger 2 Tank - Do you think if the divot was holding it on that the cylinder would be able to rotate clockwise or counter-clockwise around the piston? Meaning it can't be pulled straight back away from the gas block, but can still "spin" on top of the piston?

@ebeeby - What do you mean by the divot doesn't move at all? How would you recommend securing the barrel and gas block before torquing the cylinder? Maybe using wood boards with pressure clamps on a table?

@agalland & @ebeeby - I'm not sure how much "heat" you guys are talking about. I'm using a propane torch, lighting it up and placing it about 2-4 inches away from the tube. The left over Kroil in and around the tube starts catching fire and smoking (nothing too serious). I apply constant heat for about 20-30 seconds and then let it cool for another 30 seconds and repeat the process about 6 more times. I'm trying to install a shooters kit as well, but haven't purchased one since I haven't been successful in getting the cylinder off yet.

I haven't figured out a good method to attempt to work it loose yet either after heating it up. And I guess I will look into that leather and get some to apply to the tube after heating it.

Thanks for all the responses - I look forward to hearing more thoughts from all of you.

NO, it doesn't harm the blue at all. It has the consistancy like water so it get into areas that normal oil products can't. But, it takes awhile. My friend and I had to remove the front sight on a few M1 carbines that had been on their so tight that I was afraid I would break the tool made just for this M1 application. I put a few drops on the sight and a couple of days later the sights were very easy to remove. I think it's the simplest solution to your problem and you would be sure that the dimple is the cause. One other thought maybe you could unscrew the the whole piston & cyclinder as one unit then just soak it. I had the problem I couldn't unscrew the piston without doing damage so i just used the Cabot's. But, I wouln't use high heat because you could alter the strength of the metal and cause more harm down the road.