New Member with M211

I am in the middle of rebuilding my Airpak as we speak. Here is an exploded view for you to print off. It has been very helpful to me as I do it.

View attachment G749 Airpak Exploded View.pdf

I'm using this method of rebuild with the 5 ton kit and power piston.

http://www.steelsoldiers.com/showthread.php?70703-M220-AirPak-rebuild

USMC 00-08 said:

I am in the middle of rebuilding my Airpak as we speak. Here is an exploded view for you to print off. It has been very helpful to me as I do it.

View attachment 591325View attachment 591326

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Did you find the exploded view in the TM, or was it more complicated than that?

hambone said:

Was able to make a little more progress on the truck, thought I would get the first coat of paint on before cool weather hits, was able to get my windshields in along with the side windows.
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You're keeping that rig of yours in good repair, it looks in great shape.

Another Ahab said:

Did you find the exploded view in the TM, or was it more complicated than that?

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m1010plowboy sent it to me. No effort on my part except for a holler for help.

Question about the airpak, I have taken the 6 bolts out and the L-shaped pipe but cannot get the canister apart, taped and pried a little but no movement, any suggestions?? Thanks, Hambone

Inside is a big spring that returns and keeps the plate assembly back. In the past once I got the bolts off that spring pushed the shell off. Not sure what is causing yours to be stuck. Maybe the seal is really stuck or rusted?

hambone said:

cannot get the canister apart, taped and pried a little but no movement, any suggestions??

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I think you have corrosion inside your air canister like this. (I was not able to reuse this canister.)



Here is the lip that fits inside the canister. (These are the parts I scrounged to make a good airpak.)



Take a dead blow hammer and knock the fire out of the lip of the canister after you soak it in PB Blaster (or similar). Don't bend it of course. It will come loose, but may take a beating first.

Got the airpak apart today, doesn't look very bad inside, is there anyway i can test the pak? I know I can push the big spring in and hold my finger over the other end and it hold a vacuum until I let my finger off, could I possibly get by without having to rebuild it?

Depends on what condition your seals are in I suppose. The internals of your airpak look different than mine. Mine has a big piston looking piece that goes inside the air canister. You can see it in the background upper left of the top picture of my last post.

I spoke with Memphis Equipment a while back and they told me as long as the internals are pristine with no corrosion, scoring or pitting, you can rebuild\reuse the airpak. They told me not draining the air tanks after each use is the number one killer of these airpaks.

The only seal I noticed that had failed on mine was the cup on part AE in the breakdown. Everything else looked great.

I think I will try it before I rebuild it, I don't have the bed on my truck yet, only took 10 mins. to remove it.

hambone said:

Got the airpak apart today, doesn't look very bad inside, is there anyway i can test the pak? I know I can push the big spring in and hold my finger over the other end and it hold a vacuum until I let my finger off, could I possibly get by without having to rebuild it?


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I'm not at all an answer man, but I'm pretty sure you can't go wrong hitting any rubber seals with some silicone before buttoning it all back up.

Hoping somebody else here can either support that or shoot it down.

Air tool oil is the best thing here. In fact part of the maintenance on these is to open the plug on the back of the airpack and squirt a small amount if oil inside. The air tool oil is compatible with rubber and o rings.

Another Ahab said:

I'm pretty sure you can't go wrong hitting any rubber seals with some silicone before buttoning it all back up.

Hoping somebody else here can either support that or shoot it down.

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There is an airpak rebuild thread over in the M35 section and they recommend using Super Lube Synthetic Grease during assembly. I will be using that and either air tool oil or hydraulic jack oil in the part SturmTyger mentioned. Someone mentioned that Bendix told them to use Permatex Hydraulic Jack Oil while others say they use air tool oil. I'm a little undecided still.

I'm going to use a little dielectric grease and tool oil and keep my fingers crossed It must have been rebuilt in the past because it has a different piston in the canister than the one in USMC's pak and in the parts breakdown that Plowboy provided, thanks for all the help guys, I will keep you updated. Thanks Hambone

The piston you have that goes in the canister looks exactly like what is in the M54/M809 airpak. I only know this because I pulled one apart to compare to the G749 airpak and to get the power piston. I wonder if you have the 5 ton power piston in there too? If so, you would be all set up to use the M809 airpak rebuild kit should something not be working right when you test this out.

I thought the 5 ton air valve had a different / bigger valve piece on the end insides?

The internals are identical except for the valve on the back side of the air canister and the inside of the power piston. The G749 airpak does not have the valve on the back of the canister and the power piston from the 5 ton will thread right into where the G749 airpak one goes.

USMC 00-08 said:

Would you post up some pictures if it and it's internals when you get a chance?

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Pic of my new master cyl.

Looks identical to what I have. Are you going to take the check valve out of it?

Just the other day I was reading in the PS Mag about Army Maint guys trying to use the M34/35 master cylinder in the M211/M135. They said the G749 series had the check valve in the Airpack and that the M35 had the check valve in the Master Cylinder. They said not to have the check valve in both places! It would cause dangerous results. They explained that the check valve could be removed from the M35 master and that it would work but the effects of any pressure differences might cause issues. They also said never run without any check valves as if any air gets in the lines it would cause brake loss.

So it sounds like something that could be tried and might work if the check valve was removed?