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Warning - Stupid FNG Question - leak at fuel pump/elbow fitting

Discussion in 'The Hokey Ass Message Board' started by bruceg, Jan 1, 2010.

  1. bruceg
    Joined: Jun 1, 2009
    Posts: 52

    bruceg
    Member
    from NWATL

    Sorry for the stupid question. I replaced the mechanical fuel pump on my car. I then ran a steel fuel line from the pump to the carb. The line seems to seal properly (I got pre-flared lines, as I did a real hack job trying to flare my own). BUT - it looks like I have a leak between the rebuilt fuel pump and the elbow fitting I put in it.

    I thought I was not supposed to use a thread sealer, as it is a simple pipe thread. I'm guessing I'm wrong. What should I use that is fuel resistant?

    Between the leaking fuel fitting at the pump and the jolts from the wire to the coil I crimped wrong - I've got some fixing to do. Or at least need to keep the fire extinguisher handy.
     
  2. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,208

    HemiRambler
    Member

    You can use some teflon tape on the PIPE thread - the part you DO NOT want sealer on is the flared fitting - it's those that you leave dry as they seal on the flare and not the threads.
     
  3. Belchfire8
    Joined: Sep 18, 2005
    Posts: 1,541

    Belchfire8
    Member

    If it's leaking at the flare fitting the flare is bad or you under/over tightened it. If it's leaking at the pipe thread end you need some sealer/pipe dope there.
     
  4. plym49
    Joined: Aug 9, 2008
    Posts: 2,803

    plym49
    Member
    from Earth

    Or, worst case, if you overtightened the elbow into the pump body and cracked the casting.
     

  5. bruceg
    Joined: Jun 1, 2009
    Posts: 52

    bruceg
    Member
    from NWATL

    Thanks. I'll get get some sealer for the pipe thread and replace the line as well in case I over-tightened it. Off to NAPA!

    Don't think I cracked the casting - I'll eye-ball it. I can use the old fuel pump - it worked okay, but the vacuum part for the wipers didn't. Worse comes to worse, I'll stay out of the rain for a while. Or just run a vacuum line directly from the manifold (again).
     
  6. Astrochimp
    Joined: Sep 15, 2009
    Posts: 191

    Astrochimp
    Member
    from NE Mo.

    I would not use tape, after the filter.

    I knew a guy that lost a very $$$ race engine when a piece blocked a jet.
     
  7. If it's the type that's designed to use a steel line with a double flare then it is NOT pipe thread. Double flares seal on the end of the pipe which is why they're flared. Pipe threads seal on the threads which is why they're tapered. Which do you have ?
     
  8. maniac
    Joined: Jul 11, 2005
    Posts: 539

    maniac
    Member




    Its real easy to crack one, you must hold the body of the pump with a wrench otherwise it cracks.
     
  9. plym49
    Joined: Aug 9, 2008
    Posts: 2,803

    plym49
    Member
    from Earth

    A tip for anyone running vacuum wipers - even if also using a double action fuel pump - is to add a vacuum storage cannister. Many cars came with them. You just tee them in; the cannisters include a one-way valve. I am familiar with some used on early 60s Cadillacs that looked like a steel coffee can. They can hold enough vacuum to minimize the wipers from slowing when you stab the gas.
     
  10. lostforawhile
    Joined: Mar 23, 2008
    Posts: 4,160

    lostforawhile
    Member

    I use permatex high temp thread sealer, it comes in a little white tube,a little goes a long way,there's a reason we can use this on the airplanes at work, but aren't allowed to use teflon tape. teflon tape is for plumbing your sink. This is really good stuff, you should be able to get it at any auto parts place.
     
  11. FCCOOL
    Joined: Jun 13, 2005
    Posts: 276

    FCCOOL
    Member

    i use permatex aviation grade gasket sealant, gooey brown stuff in a white bottle with a brush in the lid, thread tape is not good on supercharged or turbo motors.
     
  12. duste01
    Joined: Nov 5, 2006
    Posts: 1,213

    duste01
    Member

    was that random?
     
  13. Licensed to kill
    Joined: Oct 4, 2009
    Posts: 214

    Licensed to kill
    Member
    from Alberta

    If you over tighten a flare fitting, you can crack the flare longitudinally. When you take the line off, the crack closes up and is difficult, if not impossible, to see, when it's tighted down, the crack opens up and leaks. If you have enough line and all else fails, cut the flare off and re-flare it. If it was cracked and you didn't cut enough off, the remaining crack should open up when you make the new flare so you will know if there's still a crack or not.
     
  14. vettes2
    Joined: Jul 9, 2007
    Posts: 288

    vettes2
    Member
    from OKC, OK

    Loctite # 565 Thread Sealant is what you need. "Suitable for exhaust systems, air conditioning fittings, fuel lines, water coolant systems and brake
    systems" This is industrial grade Pipe Sealant with Teflon. Item number 56521 comes in a 1.69 fluid oz tube. I have used this on my Three 2 barrel carb setups for 2 different builds over 15 years and never a leak. This is a thick white semi paste like stuff.
     
  15. lot's of good advice so far , but i'm not sure exactly what the problem is. it sounds like it's not the inverted flare that is leaking, rather a fitting you installed between the fuel pump and the steel line....and it's leaking where this fitting goes into the fuel pump....correct? are you sure you have the right fitting? what fuel pump do you have? i know some Holley and Edelbrock fuel pumps use 1/4" or 3/8" NPT ports , if that's the situation here you would need a fitting with male pipe threads to female inverted flare.

    you would then use sealer on the pipe thread and nothing on the inverted flare

    or i could be completely wrong...any pictures?
     
  16. plym49
    Joined: Aug 9, 2008
    Posts: 2,803

    plym49
    Member
    from Earth

    ? No, the OP mentioned that he might have to go back to the single action fuel pump.
     
  17. lostforawhile
    Joined: Mar 23, 2008
    Posts: 4,160

    lostforawhile
    Member

    I was looking for that number, the permatex is pretty much the same thing,different brand. I'm pretty sure I have the loctite brand here too. Once I learned about the stuff I got rid of my Teflon tape.
     
  18. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,027

    Mr48chev
    ALLIANCE MEMBER

    Use teflon tape on the pipe threads but don't over do it. Just a wrap to go around the threads and seal it but not so much that it bunches up.

    You want to put the tape on so that when you screw it into the female fitting the overlap doesn't bunch up. If you hold the fitting so that the the end with the pipe threads are facing you, you want to go clockwise with the tape.
     
  19. lostforawhile
    Joined: Mar 23, 2008
    Posts: 4,160

    lostforawhile
    Member

    this stuff, or the permatex equivalent, you'll never want to mess with tape again. [​IMG]
     

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