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Thread: power tube leak

  1. #1

    power tube leak

    automag gods, i need help.
    ok so i just watched the TK videos and it seems that my leak down the barrel is from a power tube oring not sealing correctly. I got this mag after it was sitting for awhile so i bought a spare parts kit.
    i went ahead and replaced all the orings that i could that were supplied with the parts kit. afterward i still have a leak down the barrel.

    so a couple questions-
    1) does the fact that it is a minimag valve matter? i think not.
    2) could the orings that came with my kit be the wrong size possibly?
    3) spacer kit would/could fix this?

    also when i pulled the trigger, the leak stopped down the barrel, but i heard a tiny bit of air passing through the on/off. well it sounded like the air pressure in the on-off built up until it sealed 100%. this lasted a few seconds before it sealed all the way. this kind of ruled out the on/off valve as having trouble until i heard that little bit of air.

    also something that came to mind was that im using the aka extreme lube. ive read stuff that says only use autolube or another kind. i was under the assumption that most of these air tool oils were the same or almost the same. could using the wrong kind of lube make weird stuff happen like orings not sealing properly?

    at one point it sounded like a bunch of liquid was flowing through the valve like a bubbling sound. could this be from using too much oil?

    sorry for the n00b questions but id really like to get back into mags and this is not helping lol.

  2. #2
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    Sounds like you need the next size down carrier for the LVL 7.

  3. #3
    i dont believe i have a lvl 7 in there. unless they came stock on minimags. it is an A.I.R. valve.
    and what would the carrier be?

  4. #4
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    Pretty sure it is a Level 7 actually. Pics would remove all doubt. It's actually a spacer, not carrier. I was typing while doing something else.

  5. #5
    ok i thought the spacer could be it. i would have to order a kit to play around with.
    it looks similar to #3&4 but that part in the middle is more recessed.

    it looks pretty old school to me

  6. #6
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    A pic of the actual bolt would be best, but a quick way to figure out is ... does the brass powertube tip have a hex head on it or a slot where you can use a coin to unscrew it?

  7. #7
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    Quote Originally Posted by baconquilt View Post
    it looks similar to #3&4 but that part in the middle is more recessed.
    That sounds like a foamie bolt, minus the foamie.

  8. #8
    it very well could be missing the foamie. the brass tube tip has a slot for a coin. and the power tube screws into the valve body housing.
    i wont be able to take a pic till later tonight.

  9. #9
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    Quote Originally Posted by baconquilt View Post
    the brass tube tip has a slot for a coin.
    Indicates Level 7 bolt. It could be the wrong size spacer. It could also be that the O-ring on the powertube tip is bad. The powertube does screw into the valve, but shouldnt unscrew very easily. If it does, there is a thin red O-ring that seals this connection up and it gets messed up pretty easily. You have a few possibilities here.

  10. #10
    hmm, when i took the power tube off the valve, there was no oring. i do remember there were fine threads for this but like i said no oring.

    it has a 225 spacer in there now. could be a tad long?

  11. #11
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    There should be a clearish urethane o-ring at the end of the threads towards the powertube tip. If you don't have one, that would be your culprit. As far as I know all Lvl 7 PTs had this O-ring. The 2 or 3 that I have here and looked at all did.

  12. #12
    on the brass piece? that was there.
    although i didnt replace it as it looked ok and i didnt have that size oring.

  13. #13
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    Quote Originally Posted by baconquilt View Post
    on the brass piece? that was there.
    although i didnt replace it as it looked ok and i didnt have that size oring.
    Yes, on the brass piece. Those probably rarely wear out, so move down a spacer size and see if this helps. There also should an o-ring inside the powertube on the valve side that the spacer rests on.

  14. #14
    yes that is correct. i replaced that one and still have a leak. i ordered a sizer kit and some foamies from AGD so that will be here in a few days.

    for now, thanks a lot for the help OPBN

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  16. #16
    yes i have seen it and i followed that diagram when re assembling.

  17. #17
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    Quote Originally Posted by baconquilt View Post
    hmm, when i took the power tube off the valve, there was no oring. i do remember there were fine threads for this but like i said no oring.
    There needs to be a red o-ring there. They won't seal without it or a full layer of blue loctite that has been allowed to set. Luke (^that luke) has the o-rings, which are kind of hard to come by otherwise.

  18. #18
    Classic and X Valve Efficiency Inserts $25 each
    Each valve comes with a powertube replacement o ring.

    this was the only thing ive seen with orings involved. is this what you where mentioning? also what would it replace? the air chamber?

  19. #19
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    Quote Originally Posted by baconquilt View Post
    Classic and X Valve Efficiency Inserts $25 each
    Each valve comes with a powertube replacement o ring.

    this was the only thing ive seen with orings involved. is this what you where mentioning? also what would it replace? the air chamber?
    No, there is a red o-ring. The replacement powertube o-ring is what it sounds like you need. Try contacting LUKE or Tunamart may have them as well.

  20. #20
    ive got a few extra ptube orings. i tried all of them that came with the kit to no avail. i even tried a few of the old ones that i pulled from the on off and actually they slowed the leak but it still persisted.

  21. #21
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    The powertube is not meant to come off. If it does, and the valve has any age to it, which it does, you definitely need to replace the red oring, which in your case appears to be missing anyway. Its not a standard part since the powertube is not ever meant to come off so you will have to order it as a special order item from one of our vendors here.

    Your bolt sounds like it is a level 7 foamy bolt, which was standard for AIR valves. If the foamy is missing, you can get a new one and glue it on. Make sure you clean the metal really well to remove any residue. Some glues can eat away at the neoprene over time, so use a good quality epoxy when gluing the new foamy on.

    If you have the spare cash, get a level 10 bolt.

    Check the condition of the sear. A worn sear can cause the bolt to sit farther forward so that the bolt stem doesn't seal against the powertube oring. You can use a shorter powertube spacer to compensate, but if the sear is worn, you should probably be ready to replace it.

    If you need a shorter spacer, you can sand down the spacer that is installed now. Place a piece of sandpaper on a flat surface such as a table top, and slide the end of the spacer back and forth across it until you remove the desired amount of metal. If you later need a longer spacer, add a level 10 shim between the powertube tip and the spacer to increase the spacer size by 0.010" in length.

    Don't worry about the oring on the powertube tip. It is only there to keep the tip from vibrating off the end of the powertube.

    On a level 7 mag, when you fire the gun and hold the trigger, there should be no air passing through the on-off. If it does, then there is a leak that should be addressed. The on-off always has the same amount of air pressure applied, it doesn't build up pressure unless the regulator isn't working. If you replaced the regulator seat oring, this shouldn't be a problem.

    Any light synthetic lubricant should work fine. All that really happens when you put in too much oil, is you prevent the orings from sealing against the metal surface. The excess liquid will be blown out in just a few cycles so it shouldn't be an ongoing issue. The biggest headache it creates is if you have a barrel on the gun when there is too much oil in the valve. It coats the breach and barrel with oil and makes the gun very inaccurate.

    Any gurgling or liquid sound in the valve is most likely an oring that is not sealing properly. You may have to take the valve apart and clean it again to make sure there isn't a piece of dirt caught in something.

    Make sure you replace the bolt spring. It is just as important as the orings and is a consumable item that wears out.
    Except for the Automag in front, its usually the man behind the equipment that counts.

  22. #22
    Thanks for the info athomas. it is helpful. i snapped a few pics last night so maybe yall can see what im dealing with. get everyone on the same page.

    here is my bolt and after looking again at it, it appears it is missing the foamie.


    here is where the power tube screws into the valve body. arrow indicates missing oring??


    and a possible problem/solution is the sear. i started thinking about a worn out sear and that could possibly lead to my problems. what say you?




    if the sear was worn out enough and not holding the bolt back far enough to seal, it would vent down the barrel correct? is this a common problem?

  23. #23
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    That sear doesn't look like it's too worn. I would wager problem is the missing power tube seal.

  24. #24
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    The sear looks fine. The bolt is definitely a foamy bolt with the foamy missing.

    The red arrow on the powertube threads is definitely where the red oring goes. It needs to be there and will leak if not in place. It is probably where your leak is coming from.

  25. #25
    it really sounds like the air was pouring down the barrel. i mean that very well could be the case and i really hope it is.
    i need more air to finish testing.

    i did notice when aired up and i pulled the trigger, the leak stopped. then when i released the trigger, i was looking into the chamber through the power feed hole and noticed that the bolt was moving forward just a tad(about 1/8 inch) and letting that air vent. i then stuck a long allen key down the body and pushed back on the bolt hoping that it would seal up and it did slightly. but thats when i ran out of air lol.

    that is also when i started thinking it could be a sear issue if it was worn down too much and allowing the bolt to rest slightly farther forward than it should and thus allowing air to escape.

  26. #26
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    It could be that without the powertube red o-ring the powertube get's little deeper than it normally would and that is causing some leak because the bolt doesn't seal properly. Just like having too large spacer in the powertube.

  27. #27
    thats a good point. never thought of that. but when the whole assembly is screwed together, it looks flush and normal.

  28. #28
    FIXED!!
    well it was a combo of either a new spacer(.215), the little oring that seals the air chamber and power tube(red arrow above), or the brass power tube tip oring.

    all is well and I thank you guys for the tips/advice.

  29. #29
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    Power tube tip is unlikely. The o-ring is there just to keep it from moving, as far as I know.

    But glad you managed to solve the problem.

  30. #30
    im not so sure which one it actually was because i installed all three at the same time. i guess i COULD go back and try for the reverse leak affect by swapping out those orings again. lol

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