Can the factory fuel sending units be repaired? What usually goes wrong with them?
Fuel Sending Unit Repair?
- Thread starter 6pk2goDemon
- Start date
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73Swinger18
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I can't speak on the electrical side of repair, but mine was full of corrosion and gunk inside the tube. I cut a piece of rag, soaked it in carb cleaner and put it on the end of a length of safety wire and pulled it through several times until it came out clean. There doesn't seem to be much to the sending unit. Just some wound wire that may be corroded and a wiper arm that may lose contact. Good luck.
TrailBeast
AKA Mopars4us on Youtube
Usually it's either the float sinks or the resistor wire wrapping where the red circle is wore through.
Check in there and see if it FUBARed.
The little finger that touches that wire winding wears down and looses contact as well.
You should be able to connect an ohm meter to the electrical terminal on the outside where the sender wire goes and the metal plate of the sender and get varied readings depending on the float position.
Oh, and good morning.
kiss
Well-Known Member
See here:
Fuel tank sending unit rebuild service
Fuel tank sending unit rebuild service
73Swinger18
✱ⓈⓌⒾⓃⒼⒺⓇ
Check it with these procedures...
One side of that little box can be bent down/open so to see inside. What you'll find...
There is a ni-chrome resistor wire in there, wound onto a piece of phenolic board. That board shrinks with age so the winding gets slack and lifts away from the board. The scrubber contact is brass. Brass couldn't wear through ni-chrome in a hunert years. The brass does wears. Contact that was once shaped like the top half of a bagel wears to a hook shape and catches the loose winding.
Aftermarket reproduction senders are different and just wrong. To have that sender rebuilt is the best route.
The original sending unit is really clean & the tube is open, but it wasn't working so we changed it out for a "new" one LOL. It's lasted 5 years, so I guess I shouldn't complain....ugh.
Thanks for your input!
Usually it's either the float sinks or the resistor wire wrapping where the red circle is wore through.
Check in there and see if it FUBARed.
The little finger that touches that wire winding wears down and looses contact as well.
You should be able to connect an ohm meter to the electrical terminal on the outside where the sender wire goes and the metal plate of the sender and get varied readings depending on the float position.
Oh, and good morning.
Thanks TB & good morning to you too!
Going to try testing it with a meter this morning. Do you know of a way to test the brass float?
I just called them $145 plus shipping both ways....OUCH
Thanks for your help!
TrailBeast
AKA Mopars4us on Youtube
Thanks TB & good morning to you too!
Going to try testing it with a meter this morning. Do you know of a way to test the brass float?
The best way I have found to test it is to shake it and see if it has gas in it.
A bit more advanced way is to submerge in in hot water and watch for bubbles.
If it leaks the heat will expand the air inside it and it will come out any leaking spots.
If it is actually the float the gauge reads lower but still works.
If the gauge only reads at one end of the scale, it's the resistor wire winding.
(Like it reads to 1/4 tank then drops to nothing as more fuel is put in)
kiss
Well-Known Member
It's expensive but it's the best option, sadly. The aftermarket fuel sending units are just...bad. Bad pickup design, incorrect linear reading design.
I had a Spectra one I ran for a few years. Didn't read right since it's linear. I know there's a little computer box you can buy that switches it but that takes a lot of messing around with to maybe make it work somewhat OK. The biggest problem I had with the aftermarket sending unit was the fuel pickup design. The car would run out of gas while there's still a couple gallons in the tank. Also since the pickup tube isn't as long when going uphill with like 1/8th tank it would start sucking air. That caused me a few scares on long trips!
Neither design is perfect in every aspect. OEM sender shown above would bounce the brass float against bottom of tank and wear a hole in it ( The softer metal always fails first ). Keeping 1/4 tank or more helps prevent that. Its lack of multiple bends in the tube makes it a self priming siphon too.
Bingo.....The float took on some water when I submerged it in a cup of hot water. I could see a few bubbles right where the lever attaches to the float.
@73Swinger18 I'm getting readings very close to your #s above with the sender on the bench.
@RedFish Will take a few closeups of the winding, brass, etc. It looks really clean...
I'm wondering if there's a method to repairing the leaking float?
@RedFish Will take a few closeups of the winding, brass, etc. It looks really clean...
I'm wondering if there's a method to repairing the leaking float?
Here's a couple pics of the inside of the sender. Not sure if these help or show anything worthwhile....
I did find the fuel line tube is loose at the cap. Does this look like factory weld ? Sure looks like a mess to me.....
TrailBeast
AKA Mopars4us on Youtube
Someone soldered that and I'll bet you have someone in house that can fix that and the float both.
I can, if you can wait till we end up in the same place at the same time.
The float is a little tricky because the same thing that showed the bubbles can suck the solder into the hole before it solidifies.
TrailBeast
AKA Mopars4us on Youtube
There's a thought, and that crack should have been brazed and that wouldn't have happened.
That has to be dealt with or it'll seep fuel.
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kiss
Well-Known Member
New plastic float, will outlast a brass one
Amazon.com: Omix-Ada 17729.01 Fuel Tank Plastic Float: Automotive
Amazon.com: Omix-Ada 17729.01 Fuel Tank Plastic Float: Automotive
famous bob
mopar misfit
I changed everything , gauge, sender, linear thing, car is rewired totally, dam gauge still aint right. I aint dropping the dam tank to fix it either !
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