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Fri Dec 17, 2010 8:05 pm

WARNING: Working on the fuel tank/ sender can be very dangerous, whether or not your tank is full or empty. Use extreme caution, and only attempt this if you are in a well-ventilated area.

Also, there is no guarantee this will work. If you've got an hour to attempt this, it may be worth a shot. Especially if you're on a budget (like me!). If you're in doubt, spend the $80 for a NOS or repro sender that works.

Items needed
-Socket wrench, 9mm socket
-Soldering iron
-Electrical solder w/flux
-3000 grit sandpaper (may be overkill, but I would err on the side of caution)
-Small needle-nose pliers
-Wire with alligator clips on ends

1. Test your fuel gauge. You can do this by touching the sender wire by taping the connector to the fuel tank. If your needle doesn't move, there are three possibilities (assuming you have a clean connection between the lead wire and connector tab). A: Your tank is not grounded; B: Your gauge no longer works (rare, but possible); C: Your sender is bad.

For A: Remove the mounting bolts and clean them and their threaded holes with a dremel. If that doesn't work, you can just connect a jumper wire to the body of the car and attach the other end to the body of the sender unit. If it works, you're done.

For B: Your gauge is broken. Extremely rare, but it can happen. I haven't had this problem, so I would suggest seeking a professional.

C: Your sender no longer works. Refer to the following steps!

2. Slowly and carefully remove the sender unit. If your tank has any gas in it, there will likely be some inside the tube. Let it drain completely, then pull it out and take it to your work bench.

3. Remove the outer tube by carefully removing the small nut off of the end. You'll have to bend down the little tabs securing it in place. Put the nut in a safe spot so you don't lose it. It's very small! Next, slide the tube off carefully.

4. You will notice the thin electrical wire that runs along the length of both sides of the middle shaft. Carefully sand the wire by LIGHTLY pinching it with a small piece of the 3000 grit sandpaper. Gently clean the wire so the contact is restored. If it is broken, you're kinda screwed. You may be able to salvage it if the break is close enough to the ends where it was soldered to, by carefully stretching it and re-soldering it to the end. If not, it's time to order a new sender =/

5. Using the same sandpaper, VERY carefully sand the contact surfaces of the contacts on the float. These are made of super-thin metal, and can break easily. Make sure the contact surfaces overlap so that they pinch the wire between them. If there is a gap, the connection will be fickle, and your gauge will not always read correctly or at all.

6. Sand down the center shaft with the 3000 grit sandpaper, again being careful not to snag the wire on anything.

7. One end of the wire is connected to ground, and the other to the end of the retainer pin for the connector wire (on the other side of the body). On the side connected to the ground, carefully solder a spot on the copper ring to the body of the unit. This will restore the flow of electricity to that end of the wire.

8. On the other side of the unit, solder the space between the pin and the connector to make sure it has a solid positive connection.

9. Test! Before putting everything back together, test your newly repaired sender by connecting the lead wire to the unit, and and the alligator clip wire between the sender body and the fuel tank. Turn the ignition switch on, and move the float up to the full position. Check your gauge. If it shows full, check it halfway down to see if the needle shows half a tank. Now try it close to the bottom, and at the bottom. If the needle is giving you a good reading, you should be good to go!

10. Put everything back together. Put the tube back on and tighten the nut- making sure to bend the tabs back up to secure it. Align your gasket correctly (do not forget this or it will leak), carefully slide the sender back down, tighten your nuts, and check your gauge once again. If it works, congratulations! You shouldn't find yourself pushing your gas-less VW as much ;)

DISCLAIMER: I just did this yesterday with promising results. As for longevity, that remains to be seen. If it stops working, I'll post it! Let me know your results if you attempt this. Hopefully this repair helps someone.

Fri Dec 17, 2010 8:56 pm

Sweet DIY, did you take any pics? I'm remedial, me likey pics :wink:

Fri Dec 17, 2010 9:01 pm

I should have taken some, but it was getting dark. When the rain goes away, I'll pop it out again and take some pics, especially where I soldered.

Fri Dec 17, 2010 10:28 pm

I did this same procedure about 10 years ago when i first bought my notch -it was still 6V and finding a new sender was difficult. I used 1500 grit (maybe higher) and carb cleaner. I tested it and it worked great. Everything was going swimmingly until the ultra thin wire barely touched the rim of the housing tube when I was reassembling it and - BINK! - it snapped.

I went without a gauge for several months.

Sat Dec 18, 2010 10:23 am

woops.

Sat Dec 18, 2010 10:29 am

Anybody within earshot would have gotten a free "french" lesson when that happened! :x

Sat Dec 18, 2010 10:37 am

I was cleaning one of mine with carb cleaner, and decided to blow it off with air. WRONG!!!

Sat Dec 18, 2010 7:27 pm

If the wire is broken right at the very end, where it's attached, it can be reconnected by fluxing and remelting the solder.

It's not easy, as that wire is as thin as a hair, but I've done it. The wire must be embedded in the solder, not just lying on the surface, as the nichrome wire doesn't stick to the solder all that well.

I had to use a magnifier hood to see clearly what I was doing, and supporting the work to keep it steady is a challenge. Once the wire is reconnected you'll need someone to help bend the flat brass spring up with a pair of hemostats or needlenose pliers so you can get the wire back onto the stretcher. Then they have to gently release the spring to tension the wire again.

If the wire is broken anywhere but the ends, you're screwed as far as repair is concerned.

Sat Dec 18, 2010 10:07 pm

One place to look for failure on a sender, is the rivet that holds the brass spring to the ground side of the wire.
My 71 failed there. Lost its connection to the body of the sender. I drilled a small hole in the aluminum of the sender, fed a small about 24 gage wire through and soldered it to the brass spring. On the outside, I grounded the other end under one of the mounting screws. I then filled the hole around wire with epoxy.

Thu Jan 01, 2015 6:11 pm

My sender failed in the same way that Russ describe, but I fixed it in a other way, the only thing not pictured is that I grind and epoxied the end of the screw, after testing that everything was okay. Also I did gently sand underneath the brass spring and aluminium with 600 grit sand paper.

Sun Oct 09, 2016 11:19 am

Thank you for this thread! It helped me get this horrible sight back into working condition. (Yes, the tank is getting cleaned next)