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another noob questions... fuel pump

Discussion in 'The Garage' started by 78Suburban, Oct 16, 2005.

  1. 78Suburban

    78Suburban 1/2 ton status

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    I am going to replace my fuel pump because SUBFAN (my msn messenger buddy) recommended it to remedy my gassy oil (said it could be a leaky diphram).... I went on Autozone.com to price one out and it asked if I had a return line or not. What the heck is a return line?
    another question,
    Should I just use a gasket to seal it back to the motor, or do I need to use some sealer as well?

    Would teflon tape seal the lines back to to pump? (I've had a leaky on that I replaced in the past).

    :bow: :bow: :bow: Thanks
     
  2. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    I use a light coat of sealer on the block and the pump and use the paper gasket. Never leaked with that setup. Teflon tape works for fuel line threads as well.
    Some vehicles have a return line from the pump to the tank to spill back excess fuel that the carb doesn't need. Mostly found on "newer" (mabye '78 up) vehicles, mabey it was an emissions thing, I really don't know what nessecitated it. You can tell by lookng at your pump, if it has only two fittings where lines hook to it (one input from the tank, one output to the carb), then you don't have a return line. If it has three (one input from tank, one output to carb and one return) then you have a return line.
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Just as 73k5blazer said except that teflon tape is not needed on the fuel line threads as that is not where the line seals. The fuel line seals on the inverted flare of the line itself. Now unless you have a fuel pump with tapered pipe threads that use a fitting before the line then you could use teflon tape on the tapered pipe threads.
     
  4. diesel4me

    diesel4me 1 ton status Premium Member

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    A 3 hoser!

    The fuel pumps with 3 lines (the smaller rubber one is the return line) is used mostly on vans and vehicles with A/C to prevent vapor lock,by recirculating the fuel back to the tank constantly it keeps the gas cooler, and keeps vapor bubbles from forming..

    The advice on the gasket is good,I use some RTV and a paper gasket when I change one--the metal lines ,I would not use teflon tape,since the threads do no sealing,as 4x4 High said..pipe threads yes,but I've never seen pipe threads on a chevy fuel pump...

    Do you know the trick for holding the pushrod for the pump up out of the way,so putting the new one in ain't such a pain in the butt??..(on small block v8's anyway)..if not,just ask!.. :crazy:
     
  5. 78Suburban

    78Suburban 1/2 ton status

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    it is the return line pump. so I just snug it up? would I be ok probably if I didn't use the rvt, or is it mandatory.

    SUBFAN was telling me about some bolt you do something to to hold the pushrod in, I'm kinda confused as to how it works though :confused: ...

    im kinda a slow learner :o
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    Yup..

    The RTV is optional..just added insurance against leaks..I like using it because it holds the gasket in place for you as a bonus!..here' is the bolt trick..

    First,loosen the 2 bolts holding the fuel pump on,but dont take them all the way out yet..then,turn the motor over by hand using a wrench on the balancer bolt,and watch the fuel pump..ot one point,it will droop away from the engine..stop turning the engine at that point..then--

    There is a bolt on the front of the motor that is right in line with the fuel pump's pushrod..If you have an air pump,this bolt is the upper one holding the bracket for it to the motor..remove it..put a bolt with longer threads (the same thread of course,it might be 3/8x16.or it could be metric-match the threads against the old bolt to be sure)...then..

    Screw this longer bolt in,but tighten it only barely snug with a wrench--it goes right up against the pushrod,you dont want to bend or scratch it!--this holds the pushrod out of the way of the fuel pump arm..now you can remove the old pump,and put the new fuel pump in without having to need three hands to install it,hold the pushrod,and install the bolts!..be sure to remove the longer bolt,and replace the original one in the front of the engine.--replace rubber and steel fuel lines-.DONE! :D
     
  7. 78Suburban

    78Suburban 1/2 ton status

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    do you mean put the old ones back on or get new ones???? all I know is that the only fuel pump I replaced on a trucked leaked gas :o
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    If they are bad..

    I've re-used old ones,but new is better(the steel line only needs to be replaced if its rusted or kinked..see that its not chafed thru where it goes behind the altenator..) A new rubber hose for the other line is a good idea..

    When you go to tighten up the steel line to the fuel pump,start the threads by hand first--they are easy to cross-thread and strip if you use a wrench..and put a wrench on the square "bung" thing welded to the bottom of the fuel pump,and hold it still while you tighten the nut on the fuel line--if you dont,you could rip it loose--that might cause a leak,a ruined fuel pump,and you'll have to start all over again..I have done it--nothing sucks more! :doah: :crazy:
     
  9. 78Suburban

    78Suburban 1/2 ton status

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    I guess I'll try to get some new rubber lines..
    about the bolt that I temporarily replace with a longer one... when I put the origional one back on the front of the block, do I need to use any type of sealer to avoid a leak?
     
  10. 78Suburban

    78Suburban 1/2 ton status

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    ttt, will I need to add thread sealer to avoid a leak with the front pushrod holder bolt?
     
  11. Smitty

    Smitty 1/2 ton status

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    Not too sure if the sealer is required on the bolt, but I always put some on since the threads go all the way through.
     
  12. 78Suburban

    78Suburban 1/2 ton status

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    if I should use some sealer, what kind... and another question.. how long of a bolt should I buy to snug up against the pushrod?
    :bow:
     

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