Should I buy a new fuel sending unit?

[Babyboomerboy]

I filled the tank with gas but the fuel gauge doesn't move. Should I buy a new fuel sending unit,($52) and see if that is the problem or is there other things I can try before buying the unit? This is for a 1950 Ford 2 door sedan V8 Thank you

 

[Brendan]

are you shure its the sender? remove the wire from the sender, and touch it to a good ground, turn on the key, if the gaudge moves , its the sender. dont let the gaudge peg out! check for good ground at your sender

 

[19Fordy]

No, don't buy a new sending unit unless it is an original OEM Ford unit made by King Sealy. The aftermarket sending units don't work accurately.

Instead:
Remove sending unit from tank and check float for cracks. Do a Fordbarn search on "gas tank sending unit" and tons of info. will appear.https://www.fordbarn.com/forum/search.php?searchid=39544858
REMEMBER:
The aftermarket gas tank sending units do not operate accurately with OEM King Sealy gauges because the after market units operate on the Ohms law Principle. The OEM gauge do not use Ohms Principle. Hence they are not compatible.

Do as Brendan says making sure you don't "peg out" the gauge because it will burn out your gauge. Remove sending unit from tank and check float for cracks. I also run a separate ground wire from the sending unit to the frame.

To check your sending unit, remove the unit from your tank and lay it on a piece of cardboard on your trunk floor. Then attach the hot wire from your gauge to your sending unit and attach a ground wire from your sending unit to ground (like your floor trunk latch.)

Then, turn on your ignition and manually move the float arm thru its range of motion to see if it registers on your fuel gauge. Gauge needle should move toward full when float arm is "up" and empty when float arm is all the way down.

The Fordbarn search shows how to remove the top of your sending unit so you can clean the points and "fine tune" your adjustment using the star wheel. It is a very tedious process so only do it as a last resort. Be careful not to break the carbon resistor inside your sending unit or the thin resistance wire.

 

[Willit Stop]

If you find that your sender is an aftermarket sender, pull it out and place the float in a bucket of water. Then place it in a bucket of gas. I had a plastic/foam float on a new sender that would float in water but sink in gas. Not completely, but enough to show about 5 gallons low. I found that a brass float from a Jeep was a quick fix.

 

[Flathead Fever]

If it has a brass float, I would check it to make sure it hasn't filled up with fuel. I worked on Ford F600-F800 trucks from the late 1970's with brass floats and they were constantly filling with fuel, sinking and the gauge read empty. They only lasted a few years in the 40-gallon tanks and then they would leak, fill up with fuel and sink. They are made from two halves of brass soldered together in the middle and they would leak on that solder joint. We would buy just the floats from Ford. Looking at the old float you could never see a hole, but they weighed a bunch and were almost completely full of fuel. For fun we would run a match around the float, and when it found the microscopic hole, they would shoot out a flame like a firework. We bought them from Ford and for some reason they came in packs of two, maybe because the trucks had dual tanks. There are a lot of suppliers claiming they fit '48-'86 Ford vehicles so maybe they are all the same. If it is the float, you should be able to get one fairly cheap. Check the sending unit first like others have said and if the gauge goes up then it's probably the float that has filled with fuel and sunk. You will also need a new sending unit gasket.

 

[petehoovie]

If it has a brass float, I would check it to make sure it hasn't filled up with fuel. I worked on Ford F600-F800 trucks from the late 1970's with brass floats and they were constantly filling with fuel, sinking and the gauge read empty. They only lasted a few years in the 40-gallon tanks and then they would leak, fill up with fuel and sink. They are made from two halves of brass soldered together in the middle and they would leak on that solder joint. We would buy just the floats from Ford. Looking at the old float you could never see a hole, but they weighed a bunch and were almost completely full of fuel. For fun we would run a match around the float, and when it found the microscopic hole, they would shoot out a flame like a firework. We bought them from Ford and for some reason they came in packs of two, maybe because the trucks had dual tanks. There are a lot of suppliers claiming they fit '48-'86 Ford vehicles so maybe they are all the same. If it is the float, you should be able to get one fairly cheap. Check the sending unit first like others have said and if the gauge goes up then it's probably the float that has filled with fuel and sunk. You will also need a new sending unit gasket.