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1940 President Fuel Pump

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  • Fuel System: 1940 President Fuel Pump

    I am in the process of fixing the exhaust and intake manifolds on my President. While it is apart, I was curious if I should pull off the fuel pump and rebuild it.. It looks extremely fragile, unique, and awesome!! Are gasket kits even available for these pumps? Should I leave it be? i would like to rebuild it because if i let my studebaker sit for more than a week in the garage, it takes forever for it to start. Almost as if the fuel is flowing back into the tank. i do not know much... actually nothing... about this unique old glass bulb mechanical fuel pump.

    Leave it be? Or pull it off and rebuild?
    Attached Files

    "Spilling a beer is the adult equivalent of a kid letting go of a Balloon."

  • #2
    The shape of that Old AC style Pump is not like newer ones from the 1950's and later, but that Diaphragm size and shape may be the Standard AC and others Size used on many Makes and Years. It does look similar.

    Then and Now Classic Auto Parts should have a Modern Alcohol Resistant Repair Kit or at least a New Diaphragm to repair it.

    The Ethanol Fuel will probably destroy it if it is not already.
    Second Generation Stude Driver,
    Proud '54 Starliner Owner


    • #3
      They used these pumps on many, many cars for many, many years. When I first got my 41 running the diaphragm failed almost immediately due to age and/or ethanol. I took it to my local NAPA and they had a reman unit on the shelf. Been fine ever since. But I am not convinced you have a problem.

      Your car does not want to start after a week because all the fuel has evaporated out of the bowl. I have the same thing. If the car has been sitting more than a few days I crank it for maybe 10 seconds without the ignition on to get some fuel up in the bowl. Then I pump the gas a couple times to pump some gas in and set the choke, turn the key on, and it fires right up. Back in the day fuel was less prone to evaporation and the cars got driven regularly so people did not notice this so much.

      The pump is dirt simple. There is a lever attached to a rubber diaphragm and a check valve (or maybe two). An eccentric on the cam shoves the lever up and down flexing the diaphragm. That sucks gas in from the tank and pushes it up to the carb with the check valves making sure the gas can only go one way.

      The glass bowl is a sediment bowl used as a fuel filter. You should empty it during routine maintenance. Unscrew the thumbwheel on the bottom of the bowl until you can get the wire bail off then remove the bowl and clean it out. Reverse the steps to replace. It is very thick glass and not fragile at all.

      If your diaphragm fails you may start getting fuel in the engine oil. You will smell that on the dipstick. If a check valve fails you will get poor fuel pressure. The only other problem I have ever had is the gasket leaking on the sediment bowl. But basically if the engine runs and you don't have fuel in the oil your pump is probably just fine. You can prove it with a fuel pressure gauge, they are pretty cheap.



      • #4
        I'm from the old-school, "If it ain't broke, don't fix it" crowd. But, if you can find a rebuilt/replacement, buy it and keep it in a secure environment for when needed. Those three long bolts on yours are for a heat shield that seems to either be removed or missing. If you are determined to keep it original, one can probably be sourced or fabricated.
        John Clary
        Greer, SC

        SDC member since 1975