Fuel Sending Unit - 1936 Roadster

[mgm60]

Replacing the leaky gasket on my fuel sending unit which by the way was homemade out roofing paper, and discovered another issue. Looks like the float arm was repaired at some point or maybe modified to work with this tank. Its' about 6 3/4" from where the arm attaches to float and where it bends to attach to the sending unit. Does this look right for a Roadster fuel tank? The fuel gauge is also not reading correctly. Only shows about 3/4 full when full.

[petehoovie]

Originally Posted by mgm60

Replacing the leaky gasket on my fuel sending unit which by the way was homemade out roofing paper, and discovered another issue. Looks like the float arm was repaired at some point or maybe modified to work with this tank. Its' about 6 3/4" from where the arm attaches to float and where it bends to attach to the sending unit. Does this look right for a Roadster fuel tank? The fuel gauge is also not reading correctly. Only shows about 3/4 full when full.

[Lawson Cox]

That there shore ain't the way Henry done it. Play around with it a tad by bending the arm a little at a time and check your progress on the dash gauge. Keep we'uns posted on your progress.

[Kube]

It appears as if someone had modified the sending unit from a different application to use in your '36. As the sending unit (proper) was identical for numerous years, this is not an unusual modification.

I'd suggest bending the arm as has been previously advised to get a more accurate reading of the fuel level.
I tend to error on the "low" side when I modify these units believing it best to depict less fuel in the tank than is actually present than more.

[terry]

And the float looks new. The original on my 36 was cork. This isn't to say that this is your problem. terry

[mgm60]

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Thanks for the feedback. Anyone that's had one of these out can you tell me if the float arm looks like its the right length for the 36? It's about 6 3/4" from the float to the bend in the arm where it attaches to the sending unit.

[Dan in MI]

The dimensions you really need are the float droop (empty - bottom of tank) and how high the float goes up to the top of the tank (full). See attached drawing you need dimensions "A" and "C" from the mounting flange of the sender. You can measure these on your tank with a ruler. A dimension may be kind of hard but you should be able to get a good guestimate to the lowest point inside the tank where the float will hit (maybe a rib?). "B" should be easier to get. Once you have these dimensions you can check your sender. I made a simple fixture out of two pieces of wood, see attached picture. The vertical piece is the same height as the "C" dimension from the top of the horizontal. Make sure the float just touches the horizontal. For the "A" dimension I used a square set to the "B" dimension added or subtracted to the "A" dimension. Subtract if the "A" dimension is below the mounting flange on your tank. Add if the "A" dimension is above the mounting flange on your tank. Now you can bend your float to meet these dimensions. Test with a gauge before installing for good (if you do this by the gas tank make sure you close off the tank so there are no fumes that can ignite. Also check by filling with measure fuel to verify 1/4, 1/2 3/4 tank.

[Dennisfly]

Here are the instructions from a new sending unit. It assumes a straight shaft and depends on tank depth.

[Dan in MI]

Those instructions are for an aftermarket Drake sender. He has a original Ford King Seely sender. The geometry may not be the same between the senders. (Pivot point location, top and bottom stops). These directions may or may not work.

[Dennisfly]

His has a bend in the float arm that the replacement doesn't have. Take it for what it's worth.

[mgm60]

Thanks for the additional info. Will make measurements and repost.

[51woodie]

When I bought my "46 Super Deluxe, the fuel gauge readings were not correct. When filled, the gauge read 3/4 full. I pulled the sender, to find it was an aftermarket unit, and the arm was too long, thus the float hit the top of the tank before full travel on the sender unit. The interim fix, until I could find a King-Sealy, was to bend the arm to shorten it. Also, the gasket that was made of red rubber dissolved in part, with pieces falling into the tank. I replaced it with a cork gasket.

I salvaged a KS sender from an old fuel tank, and the arm was rusted so thin that I had to solder on a new piece. Cleaned up the KS, bent the arm so the float stopped just short of the tank top and bottom, (see post #7) and now I have a reasonably reliable fuel gauge.