How to repair a fuel level sender unit | Ford Escort Owners Association (FEOA)

How to repair a fuel level sender unit

Discussion in 'How-To's' started by Joey_Twowagons, Jan 7, 2020.

  1. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    I'm going to try to make a bit of a How-to article about this, but I have consistent problems with loading pictures so I might make it in several posts.

    For some reason this fuel sender unit was not working properly:

    Corroded fuel pump, used Vic items 002.JPG

    It was removed by disconnecting the yellow wire and removing the two screws holding it to the hanger assembly with a 9/32" nut driver.

    Continued in next post, due to the thread screwing up when I add another picture.

    Attached Files:

  2. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Next problem is getting it apart. Dealing with hard plastic tabs is a troublesome, as it takes almost enough force to separate the tabs to break them. I poured a bit of hot water on the plastic that holds the float arm wire, then carefully pried it from its plastic death-grip using a screwdriver.

    I have a few of these units in my collection so laid them out for examination:

    Escort fuel sender 039.JPG

    The plastic housing has three tabs holding it to the metal back, I carefully compress the single one to allow the parts to separate.
    Note the broken wiper piece on the left, next to the plastic rotating part. These are molded together originally. I already replaced the wiper once, but it corroded and broke at the sharp bend. I'm jumping the gun by showing the replacement wiper in the unit on the right, because I didn't get enough pictures in order.

    Escort fuel sender 028.JPG
  3. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Here's a close up of the last repair part I made. It was made from 0.008" brass shim to which I soldered small silver contacts. It lasted about ten years before corrosion caused it to crack at the sharp bend, causing the pair of silver contacts to lose contact with the metal backing plate.

    Escort fuel sender 031.JPG

    I figured that if I made the whole wiper piece out of silver then it will be more corrosion resistant, so have been on the hunt for some silver shim stock at the local coin and scrap gold and silver joints. However the scrap pieces they had were always too thick, until I chanced upon a "silver" candlestick at a garage sale.
    This candlestick was hallmarked as sterling, and it was... at least the outer 0.008" or so, the center was some weird old plaster with a big nail in it.
    After peeling it apart and smoothing it out with the side of a jar, I got some usable bits of sheet:

    Escort fuel sender 049.JPG
  4. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    I measured up the old wiper piece, marked up the silver sheet with black marker and drew out the pattern on it. This thin material can be cut with scissors.

    The plastic piece that the wiper attaches to already had two 2mm screw threads tapped into it from the last previous repair, and I drilled the new silver piece to suit, then screwed the wiper piece on. A little trimming was needed so the crescent shaped top will clear the plastic, allowing the ends to spring up against the steel backing plate, which is the ground for the system. I adjusted the bends in the long end so that it rubbed in the middle of the resistance windings, and dimpled it so that there is a convex spot that contacts the windings to prevent it from "catching" on the individual wire loops.

    This fitting was done by inserting a number drill that fit snugly in the pieces to simulate the float arm wire, since it is so difficult to put together and take apart that arm wire.


    Escort fuel sender 032.JPG

    Escort fuel sender 034.JPG

    I didn't bother cleaning off the black marker, the gasoline will remove it.
  5. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    I reinstalled the steel backing plate and checked the sender's function with my multimeter as the unit was rotated through its range. A correct range from 16 to 165 ohms was measured, so the float arm was reinstalled, using a bit of never seize on the plastic to help avoid cracking it.
    Any grease will do, I just happened to have anti seize handy.

    Escort fuel sender 038.JPG

    I bolted the sender onto the hanger assembly and put it back in the car and eagerly turned the key on to see how it went.

    Aaargh... it's showing Full+, and the tank is only about 1/4 full.
    I realized that I had forgotten to attach the yellow wire, so I connected it. Now it works fine.

    I hope this is of some interest to someone. It's a bit of a finicky repair but I have done a few of these over the years on various cars. In the past I would just see wear, but now I see a lot of corrosion attacking brass parts in the fuel system. Especially in cars that sat for a couple years.

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