Fuel System: Gas Tank Sending Unit on 1950 Studebaker

[charlee]

I am having trouble getting the gas gauge to work on my 1950 Studebaker Champion. I have traced it down to the sending unit in the tank. Does anyone know where I can purchase a working sending unit or is there someone who can repair the one I have? The unit appears to be in good condition, but there has to be something internal that I can't see that isn't working right. Will appreciate any help.

[rockne10]

First, be certain the ground is clean and tight. Huge majority of tank sending issues is simple ground fault.

[charlee]

Gas tank sending unit on 1950 Studebaker

Thanks for your answer. I checked the ground wire. I can unhook the wire and ground it and the gauge on the dash registers full. The ground wire has a good connection on the top of the sending unit. I think the problem is between there and the float wire. Does anyone know where to get a replacement of this unit or have this one repaired?

[stephenj]

You can get a new one from Studebaker International, Part # 525548, a little expensive at $125

[RadioRoy]

I believe Rockne was not talking about the wire from the center of the sender, but about what ever grounds the body of the sender.

You might be able to fix your existing sender with a new float. Sometimes the old float gets gas-logged (like water-logged, only with gas) and it sinks.

BTW, don't ground the sending wire for more than a few seconds if you don't want to look for a dash unit next.

[charlee]

Thanks for the info. I was in hopes I could get something a little cheaper, but that may be the way I have to go. Guess I'm a real cheapskate.

[charlee]

Thanks for the information. The float is okay. I checked it. I'm not sure how the sender works but think there is something internal that connects to ground when the key is turned on. I may be way offbase. Maybe you can explain it to me. Will appreciate any help you can give.

[RadioRoy]

The way the sender works is that the power goes from the ignition switch, into and through the gauge, down the wire to the sender, through the sender and then to ground.


When you say the float is OK, you actually dipped float in gasoline and noted that it floats and does not sink?

The sender is basically a variable resistor that changes resistance with the position of the float. That's why the sender needs a good ground, either through one of the mounting screws, or you could add an external wire to a good ground.

Hold the sender up in good light, with good reading glasses, and move the float up and down throughout it's mechanical range. Look to see if there is a tab riding on a curly thing that looks like a coil spring.That is the resistor and the tab is reading different parts of it. The resistor needs to not be broken anywhere (obviously, sorry) and the tab needs to make good contact with the resistor throughout the range.

If you have an ohmmeter, you can hook it from the center post of the sender to the mounting flange of the sender, move the float arm throughout its full range, and watch the resistance change. You want the resistance to move smoothly and not bounce to infinite ohms at places in the float's travel


It might just need a good cleaning. Or most likely it is shot.

The good side is that another Studebaker six volt sender will work by making its float arm match the bends and curves of yours. The bad side is that there are less and less six volt senders out there every day.

[rockne10]

Ground is achieved by the bolts connecting the tank to the frame. More precisely just the opposite in a positive ground '50 Studebaker. Power is sent to the sending unit through the attachment to the frame, the tank and the sending unit mounting screws. Signal returns through the harness to the dash gauge, which returns its remaining current to the battery negative through the wiring harness.
I once had a Lark that sent no signal to the gauge. Dirt, rust, corrosion, whatever was interfereing with completing the circuit. I screwed a wire to one of the sending unit mounting screws and screwed that directly in to the trunk floor. Problem solved.
May not be your problem but certainly cheaper to rule it out before purchasing a new sending unit.

[RadioRoy]

I concur completely. A very simple and succinct explanation.

[whacker]

You might also review this:

http://www.gudim.com/ReplacingCorkFloats.html

[charlee]

Thanks for all the information. I will check this all out and hopefully figure out what is wrong. Thanks for sharing your knowledge.