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What to use on leaky gas line threads?

Discussion in 'The Garage' started by Pookster, Jan 21, 2004.

  1. Pookster

    Pookster 1/2 ton status

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    While installing my TBI spacer, I cant get the threads to stop leaking on the pressure side. Can I take it out and use thread tape? (the white stuff?). Is that gasoline safe? Or is there something else I should be using? Help!!
     
  2. heavy4x4

    heavy4x4 1/2 ton status

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    The threads aren't what seal gasline fittings. They apply the pressure to the flare on the end of the tube. Take the line all the way out, there should be a "gasket" in there that probably fell out or is not in the right position.
     
  3. biobry

    biobry Registered Member

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    Actually, replacing the bad line and fittings is the best way to go...but I'm sure not the cheapest. Teflon tape is chemical resistant and should give you no problems...but the leak is probably due to poor fitting of the mating surfaces of the flared fuel line and the fitting on the adapter. Any nicks in either surface will cause a leak.
     
  4. Pookster

    Pookster 1/2 ton status

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    Im replacing the acorned nut part and cutting part of the tubing off and replacing it with flexible fuel line. 14-15psi will hold up just fine.

    However, the fuel line nut that goes into the injectors, i think it might be leaking from there, so I will use the teflon tape.

    In the mean time, Any suggestions would be greatly appreciated!
     
  5. rick88blaze

    rick88blaze 1/2 ton status

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    i've used teflon tape on fuel lines many times and never with a problem. /forums/images/graemlins/thumb.gif

    Rick
     
  6. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    i've used teflon tape on fuel lines many times and never with a problem.

    [/ QUOTE ]
    But why? As stated above, fuel line fittings are compression fittings. The threads don't act as a seal on a compression fitting, as they do an an NPT fitting. The problem with using teflon tape anywhere in the fuel system is that it shreds into tiny pieces when you take the fitting apart in the future. Those tiny bits can then find their way into tiny carb passages, injector screens, etc. causing a world of problems. /forums/images/graemlins/frown.gif Leave the teflon tape in the toolbox for home plumbing projects. /forums/images/graemlins/wink.gif
     
  7. Pookster

    Pookster 1/2 ton status

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    The problem is, I feel like something is still not right somewhere, and its leaking gas- I cant tighten it anymore, maybe I did loose an o-ring somewhere. I will pickup a new o-ring just to be safe.

    Keep the info comming.

    (thanks for the warning about the pieces of teflon tape. That could suck).
     
  8. rick88blaze

    rick88blaze 1/2 ton status

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    I'm not just talking about the fuel lines on the TBI. I work with fuel, fuel piping and lines for a living. We use it all the time on all of our fuel systems. I deal with gasoline, diesel and jet fuel. And I use it as a backup in case those little gaskets fail on my TBI. /forums/images/graemlins/thumb.gif

    Rick
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    O-rings are usually in bad shape from my experience with TPI, which uses the same style of fittings. Even the o-rings on the injectors were torn up/hardened, and from what I could tell, they had never been replaced.

    Good luck finding the right o-rings for a decent price, standard ones aren't correct, they need to resist something like 200+* heat.

    I know where you can get them for about $2/each I think, if you have no luck finding them.

    As was mentioned, fuel lines are not made to use tape as the threads aren't made for it. You wouldn't use teflon on your brake lines would you? That said, I've done it before, if the fuel leaks around the tip of the flare, but not out through the fuel line/nut, it might come out of the threads, which tape will stop.

    FWIW, if it's not the "saginaw" style connectors (FI fuel lines, newer power steering line fittings) they are flare. Compression is what you use on natural gas lines and what not...typically a brass sleeve that is smashed into the copper (or aluminum) line by the fitting.
     
  10. 350350

    350350 1/2 ton status

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    [ QUOTE ]
    While installing my TBI spacer, I cant get the threads to stop leaking on the pressure side. Can I take it out and use thread tape? (the white stuff?). Is that gasoline safe? Or is there something else I should be using? Help!!

    [/ QUOTE ]

    /forums/images/graemlins/1zhelp.gif Solder them like copper pipe fittings. /forums/images/graemlins/1zhelp.gif

    Paul 'X' /forums/images/graemlins/thinking.gif
     

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