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gas tank tube thingy

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Larry_in_Tx, Mar 4, 2004.

  1. Larry_in_Tx

    Larry_in_Tx 1/2 ton status

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    The question was brought up in a thread in the garage about what the tube thingy mounted next to the gas filler neck is and what it does. I just figured it was a breather but when I pulled mine out the other day it was sealed up, no holes to let anything out. /forums/images/graemlins/confused.gif So what does this thing do? I’m thinking it may be something like a “shock absorber” plumbers put in water lines to hold pressure when the waters off so it won’t bump when you turn a faucet or something back on. There kind of built the same so it makes me think it’s something like that but I can’t figure how it would work on a gas tank. /forums/images/graemlins/thinking.gif

    I’m at a loss. /forums/images/graemlins/dunno.gif /forums/images/graemlins/1zhelp.gif
     
  2. Burt4x4

    Burt4x4 3/4 ton status

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    Ya I haven't found a solid explination yet. I think of it as some kind of equalizer. Like when it gets real hot out and the gas is warm and wants to expand...?It may be also for like when you fill the tank to the top, even though your tank is totally full having that tube is like not having it totaly full. Like the air space that is left in the top of a beer bottle.??? I am totally guessing here.
    Some one has to know the theroy behind this animal.
    I have two lines going to mine. I'm thinking of useing one of them for my fuel return line so I can keep the factory vent line and still have one line going to the pipe???
    Good question!
    Anyone???????? /forums/images/graemlins/dunno.gif
     
  3. ZZ4x4

    ZZ4x4 1/2 ton status

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    I always thought it was a gas fume condensor. The charcoal can had a line going to it , and so does the tank. I think it traps the vapor and allows it to condense and fall back into the tank. Just my made up explanation. /forums/images/graemlins/rolleyes.gif
     
  4. R72K5

    R72K5 Banned

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    vent to help fill tank easier without it backing up
     
  5. ZZ4x4

    ZZ4x4 1/2 ton status

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    I don't think he is referring to the vent tube running alongside the main fill tube (which does allow the air to escape preventing backing up) /forums/images/graemlins/thinking.gif. If I'm not mistaken, he is referring to the vertical cylinder mounted inside the bed rail which has no vents --only 3 fuel line connections on the bottom.
     
  6. Burt4x4

    Burt4x4 3/4 ton status

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    Ya that pipe bomb looking thing.
    So you guys think if I disconnect/plug one of thoes tubes off and use the inlet on the tank as a return line for my FI would be OK? But I guess we still don't know the theory behind this dude.
    Comon Greg72 whip out that super brain of yours and give us an answer????? /forums/images/graemlins/1zhelp.gif
     
  7. Triaged

    Triaged 1/2 ton status

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    I think I remember Steve Chin having a good discription of what that thing does...too bad the search function won't go that far back /forums/images/graemlins/1zhelp.gif
     
  8. mastercraftkpk

    mastercraftkpk 1/2 ton status

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    [ QUOTE ]
    I think I remember Steve Chin having a good discription of what that thing does...too bad the search function won't go that far back /forums/images/graemlins/1zhelp.gif

    [/ QUOTE ]

    NO KIDDING !!!!!!!!!!!!!!!!!!!!!!!! Much of the best info is too old to be searched for. It seems to be an unfortunate trend on this site. (lower quality w/ higher quantity of information).

    /forums/images/graemlins/waytogo.gifAt least there are new forums like THE LOUNGE.....the CK5 version of Oprah. /forums/images/graemlins/waytogo.gif
     
  9. Triaged

    Triaged 1/2 ton status

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    I'm with ya!!!

    We now have all these new forums but can't search back for any good info...what good is that /forums/images/graemlins/dunno.gif

    I wonder if the reason you can't search for it is because it was all deleated to make room for the new forums /forums/images/graemlins/confused.gif
     
  10. Burt4x4

    Burt4x4 3/4 ton status

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    I found it Dan!
    All I did was leave the number of months
    I wanted to seach blank, no number. and
    started scrolling thru, I used the word
    Vent and then looked for SteveOs name...
    and here it is....
    "There shoul;d be a minimum of three vent lines.
    One bigger one that goes to the top of the
    filler neck,and two smaller ones that route from
    either side of the fuel tank to the liquid/vapor
    separator (the "tube thing" behind the filler neck).
    The reason that there are two vent lines attached
    to the liquid/vapor separator (I'll call it the
    standpipe from here on out) is because a submerged
    vent line does not vent well enough (it's basically hydrostatically locked). If the truck has a nearly
    full tank and is tilted to one side, the opposite
    vent tube is functional and will allow air into
    the tank as the fuel pump pulls fuel out of the tank.

    The charcoal canister is a pretty simple filtration
    device that separates unwanted fuel vapors out of
    the air that is expelled from the tank (and in
    some models the carburetor). Those vapors are
    collected for ingestion into the engine when
    it is running. It does not a thing to hurt
    performance and can help make a steel gas
    tank and steel fuel lines last much longer
    because it also filters moisture out of the
    air that is vented into the tank."

    /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif
     
  11. Larry_in_Tx

    Larry_in_Tx 1/2 ton status

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    /forums/images/graemlins/waytogo.gif

    So where did Dr. Chin take off to?
     
  12. Burt4x4

    Burt4x4 3/4 ton status

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    Duno?? He is just M.I.A. /forums/images/graemlins/confused.gif /forums/images/graemlins/dunno.gif
     
  13. mastercraftkpk

    mastercraftkpk 1/2 ton status

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    Thanks for the digging Burt4x4.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  14. Burt4x4

    Burt4x4 3/4 ton status

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    No Prob /forums/images/graemlins/thumb.gif
    Have a GREAT Weekend!! /forums/images/graemlins/woot.gif /forums/images/graemlins/woot.gif /forums/images/graemlins/woot.gif
     

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