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any other suggestions for a leaky mag?

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#1 FarmerJim



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Posted 24 September 2013 - 07:00 AM

Hi all,

Just bought a LM4 and was super excited to take a test drive only to find out the magazine doesn't hold any gas.

1. Flip mag upside down (or however you fill your magazine)
2. Attempt to fill with green gas can

Expected Results:
magazine fills; you hear the magazine fill

Actual Results:
the amount of gas entering equals the amount of gas exiting out of the magazine nozzle seal (part #236)

Note #1:
If I put my finger over the nozzle seal, it feels like the magazine would fill.  Obviously my thumb can't hold back green gas presssure.

Here's what I've done so far:
* full tear down of magazine (Boobie's youtube video)
* oiled/re-oiled the 3 o-rings on the release valve (#246)
* tighted release valve
* oiled/re-oiled the base seal (#235) on reassembly

Note #2:
I noticed in Boobie's video that he tests the base seal with the magazine feed lip or essentially the top portion of the magazine removed.  When I did this, the gas just vents.

I got a second opinion from a friend and he noticed that the o-ring on the threaded side of the valve was not uniform.  Some parts of the ring looked "thinner" or "stretched" versus other parts of the ring.  I looked up another thread here and it was mentioned that the o-rings are replaceable with harbor freight rings.  Bought a pack of rings and replaced the "stretched-out" ring with the suggested A008 version.  It's definitely thicker than stock but it fits.

* Oiled up the ring and reassembled the magazine.  Still all of the gas just dumps out.  The gas sounds like it's not even under pressure / pressurizing.  It just travels from one end of the magazine to the other.

Note #3:
After the o-ring replacement and the test, I decided to reassemble the mag completely.  Still vents 100%.

Does anyone else have any other suggestions?  Or have I done all that I can?


#2 General Pickle

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Posted 14 October 2013 - 10:21 AM

That's very interesting. If the parts are still under KWA warranty I would just send it to them, that way you wouldn't have to pay for any new parts needed or do the labor etc. however if you're out of warranty or just want to do it yourself then I think the next step may be replacing the valve. It seems to me that you've done all of the obvious steps that I would have tried as well, and since that doesn't seem to be working I would guess that there's a much more serious problem with the magazine. Perhaps the magazine is warped or the threads damaged? Maybe the valve was machined improperly? KWA quality control seems to be very good for the most part, though one must expect that after being shipped overseas and through nasty customs the chances of something becoming damaged or simply missed by QC inspectors is fairly high. Anyway, personally I would get a new valve and try installing that. Usually the pro-shop has part in stock, and the prices aren't too bad.

#3 Migwl300



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Posted 15 October 2013 - 03:18 PM

I had this problem.  either you need to tighten the valve more or replace it.  just tightening it as much as possible should do it.

#4 niko_gpsy


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Posted 17 October 2013 - 11:01 AM

Your release valve sounds to be faulty. I would recommend replacing that part first before moving on to other options.  It is a relatively cheap part.

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