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CEJN fitting strip-down

Discussion in 'Fettlers Master Class' started by presscall, Apr 18, 2012.

  1. presscall

    presscall United Kingdom Subscriber

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    In this post, Camshaft asked,

    CEJN fittings can you rebuild them?


    He discovered for himself that he could but his question prompted me to take a CEJN fitting apart and compile a photo sequence and diagram of the inner workings. It's the female fitting that's dismantled here. The male fitting (over to the right in the exploded view below) is a simple component.

    1334774337-1.JPG


    Some details - I'll explain how they come together to make the fitting work in a moment. Notice in the 1st picture that one of the O-rings is sandwiched between two washers

    1334774479-2.JPG

    1334774488-3.JPG

    1334774497-4.JPG

    1334774506-5.JPG


    With the male coupling disconnected, the female coupling seals automatically thanks to this action, where the cone on that spool component is pressed by spring pressure against an O-ring that's also making a seal against the tubular inner wall of the fitting

    1334774515-6.JPG


    That's the operating phase (female fitting sealed shut) in this diagram. The male fitting has been inserted, but hasn't yet been pushed in far enough to make the connection

    1334774550-10.JPG


    When the male fitting's pushed in a bit further, the sprung-loaded detent balls are displaced by a chamfer on the fitting. They ride over a shoulder on the fitting then spring into the depression formed in the male fitting, holding it secure until the female coupling sleeve is slid back to release it.

    The seal's made by the other O-ring in this configuration

    1334774534-8.JPG


    This is the spring, located beneath the outer sleeve, that holds the steel detent balls in place and gives them their spring loading

    1334774542-9.JPG


    Something about a source for replacement O-rings.

    Here's a diagram of a Primus Omnifuel from sponsor Base-Camp

    Primus Omnifuel


    The O-ring (part number 731905) is the one on the spindle - £2 from sponsor, and also contained in the Omnifuel spares kit. It's the blue O-ring in this photo, alongside a CEJN original

    1334774525-7.JPG


    Some final notes on dismantling and reassembly of the CEJN female fitting.

    It's simply done, the spring clip in this photo is carefully prised out of its retaining groove ...

    1334777621-11.JPG


    ... the male fitting has then to be pushed in ...

    1334777632-12.JPG

    ... and the outer sleeve is slid off over the male fitting, which also pulls out, leaving this view

    1334774542-9.JPG


    The detent balls retaining spring is then simply slid back with a thumb nail and each of the three balls is allowed to drop out. With those removed, the inner components slide out of the fitting, perhaps needing a bit of gentle prodding with a smooth-ended rod from the fuel inlet end.

    Reassembly is the reverse of that, as the saying goes.

    NOTE: for larger reproductions of the exploded view photo and the drawing of the sectioned fittings, click on the white cross in a green square 'Attachment' symbol below and click on 'Attachment: 1.JPG' for the photo and 'Attachment: 10.JPG' for the drawing. To return to the post thread, click on the 'back' button on your browser window.

    John
     
    Last edited by a moderator: Jul 2, 2015
  2. Big BTU

    Big BTU United States Subscriber

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    excellent post as usual John.

    thanks for the thorough picture breakdown and also the diagram.
     
  3. camshaft

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    Thanks John , awesome write up
     
  4. toonsgt

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    Excellent as usual, John.

    Is there any noticeable difference in the hardness of the blue and black o-rings? I had some dealing with other blue ones and found them VERY soft compared to the ones from my nitrile or viton kits.

    Mike
     
  5. presscall

    presscall United Kingdom Subscriber

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    Toonsgt asked,

    I believe there is, Mike, but so far so good with the CEJN coupling I'm using a blue replacement in and since Primus use it in their Omnifuel I've no worries about fuel incompatibility.

    Camshaft's report in his post of a leak from one of the original spec O-rings in low temperatures suggests to me that a slightly softer compound might perform better in sub-zero conditions, so maybe that's something in its favour.

    Quick fix for a leaky fitting occurs to me, something that should be achievable in the field (but disassemble/assemble on a tarp to catch the bits!) ...

    Because there's one O-ring to seal the female fitting when it's disconnected and the other one engages with the male fitting and seals the connector when connected, the fitting is always carrying its own usable spare (the one that shuts off the female connector when disconnected from the male).

    Pound to a penny it'll be the O-ring making the seal with the male fitting that's failed, and since the other one really isn't needed in our stove applications because the control valve will shut and prevent fuel flow when the flexi hose is disconnected from the pump, the redundant O-ring can be swapped with the suspect one. I say 'swapped' and not 'discarded' since it'll still be needed to serve as a spacer in the mechanism if not as a seal.

    John
     
  6. RonPH

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    I will jump on this topic to find out if the o-ring being sold by HarborFreight as HNBR which is colored green and I have seen also on some of the newer bayonet type connectors on the Nova is any better.

    John, again thanks for a very informative presentation of the parts on the CEJN.


    Ron
     
    Last edited by a moderator: Jul 1, 2015
  7. toonsgt

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    John, my Nova has no control valve on the pump, so no spare there, but I see your point. In a pinch, you can at least use the stove if the mating o-ring fails. Or, I misread your point.

    Mike
     
  8. toonsgt

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    Ron, a quick search brought some MOSTLY great initial info on HBNR. Better in every category for our use except low temp flexibility.

    Rubber chart.

    Mike
     
    Last edited by a moderator: Jul 1, 2015
  9. RonPH

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    Hey Mike, so its not good for cold climates such as in snow for the HNBR. Well, I really dont plan on snow camping so its good then for that purpose. Thanks for the chart. Makes for easy reading.

    Ron
     
  10. toonsgt

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    Probably fine for snow, but those going to the poles or Everest may want to think twice.

    Mike
     
  11. SNOWGOOSE

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    Really excellent John, superb photography backed by clear and concise writing.
     
  12. camshaft

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    I used automotive Orings and have had them in a test container with white gas for a week. They have held up with no issues so far.

    http://classiccampstoves.com/threads/21340

    The original Orings I had inside my CEJN connector where on the stiff side. Which I can understand being the original Orings. And would make sense why the connector was leaking in -10c temps

    Thanks again John, my repair was a tad tricker because my fuel hose is still attached. But not impossible
     
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  13. Doc Mark

    Doc Mark United States Subscriber

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    Good Morning, Presscall,

    Your report and photos on this topic are absolutely first rate, John!! Thank you for taking the time to suss this out, write it down, take the photos, and then post them here!! Well done, and much appreciated. I've always had a niggling distrust of those fittings, ever since my Optimus #11 came to live here, NIB, and the fitting leaked, right out of the box! I contacted A&H, as I was already buying parts from them, even way back then, and they sent me a replacement, no charge, as I had the original sales receipt, and they were an authorized service center and dealer for Optimus at that time. I think I still have that leaky connector around here, someplace, and will have to give your instructions a try. I'm sure it will work like a champ! Thanks, again, John, and God Bless!

    Every Good Wish,
    Doc
     
  14. camshaft

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    I just wanted to ask a quick question..
    http://classiccampstoves.com/threads/19406

    Does anyone know of a alternative connector that could be used in place of the CEJN ?

    Why I ask is that these connectors are not available in north America. And are a small fortune to import into Canada.

    I'm attempting to take a older Nova and attach another brand of pump onto it. So it would be great to have quick connect at one end of the hose.

    thanks
    cam
     
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  15. RonPH

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    Cam, there is, you need to Google RECTUS connectors/couplings and find the right one to suit your needs. I have ordered some before and offered them to a few. However, this was through a friend of mine. You can also do a search on the forum search bar and you will come up with my posts.

    Ron
     
  16. camshaft

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  17. RonPH

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    Cam, yes, I do have the part number.

    Female barbed - 20KATF03MPX
    Female threaded - 20KAAF05MPX
    Male Barbed - 20SFTF03MXX

    You do know that these couplings are smaller than the CEJN. Let me know if you do find a Rectus supplier in your end as I may need other parts.

    Ron
     
  18. bajabum

    bajabum United States R.I.P. Subscriber

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    Listed under stainless steel, 20KA
     
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  19. brassnipplekey

    brassnipplekey United Kingdom Subscriber

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    John.. & ALL .
    ... What an excellent thread .
    CCS ... Cheers .
    316L 20KA.mmmmmmm.
    Y'all keep yer Nipples,Spirit Cups ,Barbs & Spigotts clean.
    Keep grit & other bodies out of your coupling members ...OOPpsss what a give away .
    White Black Blue Green Wet Snow ICE NON StOp Torrential (tropical )1/2 warm :-) wetness .& Etc
    Probably wont ,majourly, disable a stove .. Grit & grime in its gubbins will ...
    Component stoves , I see as some form of a techknowresponsibility .
    Give me a Litre of Kero & a 3 legged brassy .
    Ohhhh Mrs , I do like the old ones .
    Keep it blue .

    nick
     
  20. greggabi

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    I have a Brunton Optimus Nova from about 2003 or so.
    Made in Sweden, Cejn, etc.

    I have the exact issue described here -- Leaking fuel from the coupling but only in very cold conditions. It just happened for the first time now at about 6 degrees Fahrenheit. Luckily this was a pre-trip test.

    The suggested fix of replacing the o-rings seems simple enough given these precise photos and that stellar drawing.

    But, where can I get the replacement O-rings? What size & type do I need?

    I am near Chicago.

    Cheers.
     

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