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Fhead Fuel Pump Rebuild

Discussion in 'Early CJ5 and CJ6 Tech' started by Don X, Mar 28, 2021.

  1. Mar 28, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    I need to rebuild my fuel pump and have some questions.

    There seems to be a big difference in the price of rebuild kits. Obviously quality accounts for most of the difference but what should I look for and what should it stay away from?

    Having trouble removing the glass bowl. It doesn't appear to be threaded but I don't want to force it and break it. What is the correct way to remove it.

    Also the spring on the bottom doesn't want to release. Correct way?

    PXL_20210328_181321353.jpg
     
    Don X, Mar 28, 2021
    #1
  2. Mar 28, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    The glass bowl is probably just stuck on there. Haven't had one not come off fairly easy though, maybe soak it in a bit of gas? You're talking about the one with the bail holding it down I assume?
     
    Glenn, Mar 28, 2021
    #2
  3. Mar 28, 2021
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    Soak the top/glass bowl in mineral spirits overnight. The spring attached to the arm or the spring under the diaphragm? Push the arm spring in until it clears the tip of the spike. HINT: Wear your PPE. To remove the diaphragm and spring you have two choices.

    1. Using a narrow tool to support the inner arm up, push down and angle away from the flange. This method requires time. Unless you are blessed, you won't unhook it and good luck getting the new one in.

    2. The easy way. Using a punch and small hammer, drive the pivot pin out of the housing. The arm will fall out. Turn the housing so the flange is parallel with the work surface and press in on the diaphragm. The inner arm will fall out and you can remove the diaphragm and spring.

    If the glass is still stuck you can use a small rubber hammer and tap gently around the base.

    Kits? Steer clear of O/A. "Seal Tested" is what I use. Check back when you're ready to put it back together again. Oh. And keep your swear jar handy.
     
    Last edited: Mar 28, 2021
    scoutpilot, Mar 28, 2021
    #3
    dozerjim, Glenn and Don X like this.
  4. Mar 28, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

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    Yep.
     
    Don X, Mar 28, 2021
    #4
  5. Mar 28, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    I've looked at it closer. The only reason I was looking at it was it's been sitting for 4 years. Most of that in the dry, hot southern California desert so I'm concerned about it having dried out too much. If you look closely at the picture I posted you'll see the the rubber is still pliable. The part of the spring that can be seen looks good and the lever action seems normal.

    I've got the top soaking in gas. If everything looks good after I open it up I'm thinking about a thorough cleaning and put it back together. I have a backup dual action pump on the shelf that I carry as a travel spare. Also an electric pump might be an easy trail back up? I'm still running 24 volts but those seem to be readily available. Even with low psi.

    Options. I've got things to consider.
     
    Don X, Mar 28, 2021
    #5
  6. Mar 29, 2021
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    That diaphragm is the old type. Ethanol will not treat it kindly.
     
    scoutpilot, Mar 29, 2021
    #6
  7. Mar 29, 2021
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    Scoutpilot,

    I think that explains the wide range of price differences in the kits. The more expensive kits I have looked at were USA made and of modern materials to handle the E-gas. The cheaper kits make no mention of that.

    But, I have not found kits branded "seal testest", which is a brand I recognize from my youth. Do you have a source for that?

    Around here 100% gasoline is available at most places because we are surrounded by lakes and alcohol is a real bad thing for 2 Cycle outboard boat motors. That is what I run in the old engines I have whether Jeeps, tractors, or other equipment.
     
    Oldpappy, Mar 29, 2021
    #7
    Mark T. and scoutpilot like this.
  8. Mar 29, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    Everything checked out well. Cleaned everything and reassembled it. I had to cannibalize the cork gasket from my spare because the one I removed tore off a very small section. The replacement from the other pump looked like it was brand new making me wonder if I ever used it.

    At this point I'm comfortable going with what I have. Hopefully no problems down the road (trail?).
     
    Don X, Mar 29, 2021
    #8
  9. Mar 29, 2021
    Mr Vaughan

    Mr Vaughan

    if it were me, i probably would experience total pump failure, as my mother is a murphy (murphys law). if everything goes downhill, you can take the windshield and hood off and lean over and dribble fuel into the carb
     
    Mr Vaughan, Mar 29, 2021
    #9
  10. Mar 29, 2021
    scoutpilot

    scoutpilot Member

    Asheboro, NC
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    scoutpilot, Mar 29, 2021
    #10
  11. Apr 1, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    Anyone who has installed a fuel pump on an fhead knows the left bolt can be difficult. Has anyone here installed studs into the block? If measured right to allow for a deep socket it should be easier to start a nut on the stud as opposed to starting a bolt into the block. Thoughts?
     
    Don X, Apr 1, 2021
    #11
  12. Apr 1, 2021
    Mr Vaughan

    Mr Vaughan

    or who has removed/replaced the fuel pump several times because of improper reassembly and troubleshooting :banghead:
     
    Mr Vaughan, Apr 1, 2021
    #12
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