Fuel Sending Unit Repair Advice?

[Mike Wessinger]

I have been on these forums for some time, and seen many threads over the years about fuel sending units. I am looking for some advice I haven't been able to find in the older threads.

Quick backstory--my original in-tank sending unit lasted 45+ years. In the past decade though, I have now seen my 4th cheap replacement stop working. In the hopes of figuring out a way to fix them one day, I never discarded the three previous units, just stuck them on a shelf in my shed.

Today, I pulled one of the old non-functioning units off the shelf, took it apart, and with my electrical tester noted the ohm reading was correct as I moved the probe through the range inside the contact arc inside the float arm contact housing. I cleaned everything up, put it all back together, and got a good steady reading throughout the range. Next step, I hooked it up to the fuel tank sending unit wire in the truck and the ground point in the cab with alligator wire clips, turned on the ignition, and watched the fuel gauge needle move as I moved the float arm, just as it is supposed to do. For the heck of it, without any cleaning or fiddling, hooked up the other two "non-functioning" units to the alligator clips, and watched them work just as perfectly as new, as the fuel gauge needle swept from empty to full as I lifted the float arms.

Three "dead" units are now back working. (The current dead one in the tank may work again if I leave it on a shelf for a few years.) The four sending units I purchased over the past decade have ranged from cheap eBay stuff, to not nearly as cheap parts from more reputable online retailers. All show up and look like they were stamped out and assembled in the same factory somewhere in China.

And finally, to the whole point of this post. What can one do to help these cheap sending units continue to work once submerged in gasoline for a couple years? Anything? Is there anything I could do before dropping one of the resurrected sending units into the tank to hopefully get a few more years use out of it?

[61hawk]

Do you have a pinhole in your float causing it to fill up and not work... until the gas evaporates out of it?

[Mike Wessinger]

Originally Posted by 61hawk

Do you have a pinhole in your float causing it to fill up and not work... until the gas evaporates out of it?

Good thought, but not in this case. All of the older units I confirmed were no longer working when I pulled them with my test meter. I am guessing maybe something happens to them submerged in the tank after a few years which may interfere with the contact inside the mechanism with the pickup. But that's just a guess right now, and doesn't explain at all why all three formerly "dead" units now work. Thanks.

[Mike Wessinger]

Originally Posted by 61hawk

Do you have a pinhole in your float causing it to fill up and not work... until the gas evaporates out of it?

Pulled the "non-working" sending unit out today and thought of your suggestion. I popped the float out of the wire loop, gave it a shake, and sure enough, it was half-full of gas, just as you suggested. I wiped it dry with a paper towel and could see gas coming out through an almost invisible hole in the side--not on a seam where you would expect it, but just a random spot on the side.

I think I may take the other two now working units, sand down the floats on both, and completely coat/encapsulate them with JB Weld so I will have a couple spares on hand.

Thanks again for the suggestion--you were spot on.