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Fuel sending unit has a cork float on the 61 CJ5

Discussion in 'Early CJ5 and CJ6 Tech' started by Drive28, Dec 1, 2014.

  1. Dec 1, 2014
    Drive28

    Drive28 Member

    Cape Cod...
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    Oct 16, 2014
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    What year CJ5 did they stop using a cork float on the fuel tank sending unit?

    I pulled the driver's seat this past weekend to repair some of the upholstery and I removed the fuel tank sending unit to examine it while I had the seat off. I was surprised to see a cork float....never had a vehicle with one.....most of my classic vehicles had original brass floats.

    Have a replacement unit ordered with a brass float because this original one seems to have a break in the resistance winding and I don't want to be using a dip stick to check the gas level forever. Been seeing this with several old fuel sending units. The ethanol in todays gasoline has such an affinity for H20 that the moisture quickly corrodes the fine resistance windings on these older sending units.
     
  2. Dec 1, 2014
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    My 66 was cork (originally).
     
  3. Dec 1, 2014
    1967 CJ5A

    1967 CJ5A Mike 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Raleigh, NC
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    My 67 was also cork. I replaced the sending unit with an Omix one (plastic) because the old one burned up. When I fill up, the gauge stays pegged above full until a couple gallons are gone. Then it drops fairly quickly, and almost reaches empty with maybe 4 gallons left and moves really slowly towards E. I've never run it out though. Not sure if its adjusted wrong or just a junky sending unit.
     
  4. Dec 1, 2014
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    Mike you have to calibrate the new sender to your tank. The tank is about 6" in depth so you have to bend the float arm so the float will not go any lower than about 1/4" from the bottom.
     
  5. Dec 1, 2014
    Drive28

    Drive28 Member

    Cape Cod...
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    Oct 16, 2014
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    Good to know Walt. I'll set up the new one for 1/4 inch clearance from bottom.

    It sounds like they were using cork up to at least 1967.
     
  6. Dec 3, 2014
    chris_bar

    chris_bar New Member

    Mid Tn
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    Apr 14, 2014
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    Plastic floats have a tendency to crack and fill with fuel, then sink. I replace mine (plastic) with a brass one, also make sure if it offsets to one side of the sender arm that it doesn't interfere with the baffles in the tank found that out when my gauge didn't read anything but full.
     
  7. Dec 3, 2014
    Drive28

    Drive28 Member

    Cape Cod...
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    Oct 16, 2014
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    My original 6 hole unit with the cork has staggered/keyed hole spacing so it lines up the float away from the baffles. I am hoping the replacement I ordered has the same hole spacing so I don't have take a drill to it.
     
  8. Dec 3, 2014
    Drive28

    Drive28 Member

    Cape Cod...
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    My original one with the cork has keyed/staggered hole spacing so it lines up the float away from the baffles. Hope the replacement I ordered is the same.

    I repaired the upholstery form the driver's seat. What a messy job that was getting the covers off the frame........there must have been 50 years of nuts, acorns, mouse nests and mouse turds in the seat back
     
  9. Dec 4, 2014
    chris_bar

    chris_bar New Member

    Mid Tn
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    On the sender yes, but the ring indention on the brass float itself was not centered so it offsets on the arm (just replaced the float not the entire sender assembly), I installed mine backwards and the float touched the baffles in the tank. Re-installed with the float flipped and it clear everything.
     
  10. Dec 4, 2014
    Drive28

    Drive28 Member

    Cape Cod...
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    Thanks Chris_bar.....good to know....UPS just delivered the new unit today with the brass float.
     
  11. Dec 4, 2014
    KJRoss54

    KJRoss54 New Member

    Elgin, Ok
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    My 66 V6 was cork.
     
  12. Dec 6, 2014
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    I don't think there's anything wrong with a cork float... IIRC the ones I've seen have been dipped in varnish of some kind to seal them. As long as the varnish does not dissolve in modern fuels, and the cork does not get saturated and sink, they should last indefinitely. I have had brass flats that were worn out and leaked - cork can't leak...
     
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