Fuel Gauge Sender Unit replacement advice

[JavierB]

Hey guys.

so next up is getting a working fuel gauge.  the gauge seems to work fine, or at least it will register full if I short it.  So I pulled out the old sender unit and it looks like its been through a few wars, so I'm replacing it for sure.

NOTE: I removed this through the rear access hole in the trunk.  BIG MISTAKE.  I can't imagine a scenario in which the unit, even if was in perfect condition could be removed without being completely ruined in the twisting, yanking, bending necessary to get it out that way.  For the replacement I plan on removing the rear seats.  (the instructions in the workshop manual simply say "remove" which is a bit comical.  I know for a fact I'm going to be on this board tomorrow asking for help.)

But to the task at hand: I'm buying a new sender unit.  any advice?  There is one from SI, but is that the same low tech item I just pulled out?  There is also a less expensive item from AvantiParts:

https://avantiparts.biz/sender-gas-tank/

and also a unit from Classic Instruments:

https://shop.classicinstruments.com/sn35

Wondering if anyone has any recommendations/advice on any of these or a better alternative?  Both the AvantiParts unit and the Classic Instruments use a plastic neoprene float, but I'm not sure about the SI unit.  Thanks for any ideas.

 

[JavierB]

Okay, well, I didnt get any feedback so I went ahead and ordered the one from Avanti Parts.

I'll post if it was a successful install next week!

[Kyle]

Let me know how it goes. I just pulled my fuel tank.  Like you need to select new sender or go with existing.   

[Desert Driver]

The replacement sender should work just fine. Before installing it, test it using a multimeter. When the float is all the way up, there should be enough current to make the gauge read "Full". The sender aint high tech, and there are plenty of "how to" videos on YouTube.

[JavierB]

Okay!  The rear seat removal was actually EASY.  Literally the first thing I've done on this car that was super straightforward and simple!  Looks like the previous owner installed new gas lines and brand new filter up top.  The condition of the gas sender, covered in rust, makes it no surprise that its not working.  🙂

 

 

[Desert Driver]

Hopefully that filter is catching all the rusticles from the old sender! It's a lot easier to work on the fuel tank by removing the rear bench seat. Another issue I had was the misalignment between the filler tube and the tank itself. A rubber hose is used between the two, and if it's not perfectly aligned, gasoline pumped into the tank will backflow and shoot out over your car. I was able to loosen the clamps on mine and rotate the hose, but sometimes it's a real booger to rotate. Keep up the good work!

Edited August 20, 2021 by Desert Driver

[JavierB]

UPDATE:  The sender unit from AvantiParts.biz was a relatively simple install.  Its a Stewart-Warner unit, and it comes pre-cut to size from AvantiParts with a gasket and new bolts.

One Word of Caution: Most Avanti tank senders are apparently secured with 10-32 Fine thread bolts.  My 1981 is NOT.  so I spent most of a morning cursing my poor alignment skills in trying to get wrong threaded bolts into the holes before checking that simple thing.  I reused my old bolts and it took just minutes.  So I'm not sure what years/numbers may be different, but don't assume, like I did, that the bolts in the kit will work.

[Kyle]

Just pulled my fuel tank. Similar condition of sender.  Had fuel tank cleaned and sealed at local radiator shop.  Will install next week.  

Did you take any steps for controlling noise before replacing tank?  Dynamat or similar? etc

[Desert Driver]

I applied HushMat as well as carpet pad to minimize noise and vibration from the rear bench seat springs. HushMat sticks to any clean surface, and the padding is held in place with Scotch Super 77 adhesive. Padding is on the fiberglass cover over the fuel tank, and on top of the driveshaft tunnel.

Edited August 29, 2021 by Desert Driver

[Kyle]

Great picture.  Thanks.  

[Kodjo]

Does it work? The amount of HushMat seems overkill to me.

[JavierB]

I didnt do the extra sound proofing at this time.  Removing the seat was trivial, so I figured I would get back around to that in the future.  Many more pressing concerns first!  Would like to hear your results and if its a noticeable improvement.

 

[DaytonaR2]

Be mindful that the holes in the sender and gasket are specific to orientation. They holes are not equally spaced.  My new sender had the float swing toward the passenger side versus the drivers side on the original.  That is where the holes aligned.  It seems to work great.  Far better gasket too.

[pantera928]

Both my old original and the new one have the float oriented toward the passenger side of the tank