VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc universal fuel tank sender

Has anyone used a universal fuel tank sender from The Filling Station in a 6 volt car and if so did it work good?
Thanks for any replies.

I don't remember whether I got it from TFS or Chevs of the 40s but the universal I bought worked OK after some modification. The tank in my 38 is so shallow I had to shorten the float rod quite a bit. It was so short the float couldn't overcome the stiffness of the rheostat. I ended up putting an extra float so it would rise. That worked OK but it wouldn't fall for the same reason so I also had to add a small lead fishing sinker at the tip to give it enough weight to overcome the rheostat. After a few tankfuls of gas it loosened up and worked normally. I eventually found a working original on ebay and have it in the tank now. I gave my old universal to someone who needed one a few years back.

I received one from Chevs of the 40s. Works OK but we do not have it calibrated correctly. We just remember that 3/4 = full.

OK Thanks guys, I need one for my '33 coupe. The tank in it is quite shallow too. I may have the same problem you did Tiny!

What I found when I did mine for two separate vehicles. The first universal sending unit I bought did not allow me to remove the arm at all. I got it to work correctly with some imaginative bending of the rod and figured that was to be the norm. The second unit I bought allowed me to remove the rod from the unit and then rebend it and reinstall it to acquire the correct stroke to match the tank. So when you shop for your next sending unit, find one that shows the float/rod assembly detached. The one I got was actually prebent and put together with a nice clean 90deg bend but it was easily disassembled with a gentle pry of the rod. Once I got everything measured out, I just rebent another 90, snapped it back together and all was good

So, I started by measuring the depth of my tank. Let's say it was 6" deep. Draw a side view of that 6" on something flat... the top line for the top of the tank and so-on. Then lay your sensor on its side to where the top of the sensor is in line with the top line you have drawn. You can then hold your float rod in place against the sensor arm (the part that stays attached to the sensor and swings up and down with the float rod) and swing it up and down to decide how long or short the rod has to be.

There may be a situation where the rod length works well at the top of the stroke but then it doesn't go down the full 6". This can be correct by some bending of the rod itself while also adjusting the length. I used a piece of scrap brass rod (it's soft and easy to bend) for all my preliminary bends to sort out what angles and length finally worked well.

You want the bottom of the stroke of the slider to match the lower 6" mark and the top of the stroke to match the upper 6" mark. Keep in mind that the float itself will distort your measurement a bit but with a little patience it'll get pretty close.

Also refrain from attaching the rod to the sensor arm until you are fairly certain you have it all bent correctly. I spect it won't tolerated any stress during any of this process.

Good luck

This is the type of sender I was referring to. The main shaft has to be adjusted as short as it'll go to not bottom out on the tank. That leaves the problem that the float arm must be very short so to not bottom out on the tank which lead to the issues I mentioned.

https://store.fillingstation.com/de...UNIVERSAL_FUEL_SENDING_UNIT_030_OHM.html

Thanks for the info guys! I discovered that TFS also sell an original type for $ 20 more, maybe it would be worth it considering the problems getting a universal to work?

I believe this is the one I used. Not sure how to copy the link but the FS part number is 1515483. There are a few different ones shown but this is the jist of the design. The rod sets in a hole with a 90deg bend and the swinging arm has a clip that holds that rod in place. A nice design. It won't twist because of the 90 bend. Lots of room to manipulate. Seems to float and drop just fine as my rank is just a 6" deep too. Works fine, lasts a long time... we hope.

And it kinda just worked out as the one you showed was on back order at the time (I had actually ordered both for comparison) so I said "just send me the one you have", and this was the one they sent.

This is what the OEM sender looks like for my 38. I assume it's the same for your 37.

Thanks for the pictures. The sender is for my '33 coupe. It has the original sender in it but it doesn't work. I ordered an original from TFS but they called and said it is out of stock. They are hoping to have one in about 2 weeks.

Have you determined why the sending unit does not work. When I took mine out of my 31, the arm and gears were frozen up and the cork was near powder. I cleaned everything up and got things moving and purchased a new cork from the FS. I did have to remove the rivets and removed the cover. With the cover removed you can clean it up and make sure there is good contact with the arm contact (I believe there is a small spring there) and the coil. Make sure there are no breaks in the wire on the coil. An ammeter can help here to test for continuity and resistance. Have some fun and try to fix it if you can.

This car was a basket case that sat in a grove for years. The fuel tank and sender were full of rust and varnish. I cleaned up the sender the best that I could but it was pretty grungy. The gauge always reads i/2 full no matter how much gas is in the tank. Pretty sure the gauge is good and everything that should be grounded is. I have been putting up with it not working for 40 years and decided to try and fix it in my old age! LOL

There's a really good YouTube video on how to test your gauge. Search Fuel Gauge Test and it should come up. I always thought it would be more difficult but it's not. Get your gauge to do what it's supposed to do completely WITHOUT the sending unit connected... and the rest is down hill.

Until you do that, you're kinda running blind.

Good luck

Thanks, I am pretty sure that I tested the gauge a long time ago. I should probably do it again just to be sure.

The only thing I've never gotten a full understanding of is how to test the gauge to find out which resistance the sending unit needs to be. Still don't know.

GM up to 1964 - 0-30 Ohms. GM 1965-1997 - 0-90 Ohms. GM 1998 & up - 40-250 Ohms. Just did a google search and this came up. 0=empty and 30-90 full

Yes...but. If you have an unknown gauge and no other information, how do you know which resistance range sending unit it requires to give accurate readings?

You are asking the right question. Unfortunately there is not an easy way that I know to match a sending unit to an unknown gauge.

The fuel gauge responds to induced current. It is really an ammeter. The induced current changes as the resistance changes in the sending unit.

I did a google search and found a post that explains how to test a known gauge. Identifying the gauge would be best . You could test by trying a known sender (or resistor) of 30 ohm or 90 ohm and see what the gauge reading is.

I have a unit that checks the guage resistance (I have not seen another 1). 1 method of determining what resistance a guage requires is to connect a variable resistor in place of the tank unit adjust the resistor to get a "full" reading on the guage then with a multimeter measure the variable resistor. Then repeat the process for a "empty" reading.
Tony

Admittedly that is the only way I can think to do it. Thanks for that.

I was HOPING for some magical multimeter setting that would exclude the variable resister but I guess not.

Such is life, huh?