During the last days I fixed a bunch of original fuel gauges.
I thought I´d put a "How-to / step-by-step" together, so everybody here on the Gee can see that there´s no magic involved...
It can be done with simple tools and allthough it won´t reach the grade of a professional restoration (like Sean´s work), it will work.
A dirty, well used, original 6 Volt two connector fuel gauge, the WWII jeep standard model.
The resistance between the two posts is about 36 Ohm here. That´s ok. I measured values between 30 to 42 Ohms here.
here´s the problem of 99% of all fuel gauges.
The resistance between the left connector and the housing is infinite here. That´s wrong!!
Ok, so we´re going to dismantle it:
I´m using a special tool, but a big screwdriver will work, too.
Here´s a closeup of my tool:
When you bent the lid a bit, a small pair of pliers will do the rest:
After going round the lid with the pliers, you can remove the lid. Then you´ll have this here:
Some parts and a lot of dust and dirt...
To get the mechanics out of the housing, you´ll have to remove the two nuts from the connectors.
I put them in my bench vice with a rag to protect the thread...
Then I remove the nuts with some pliers...
Then you can completely dismantle the gauge:
Make sure not to loose the two insulator washers!
And here we see our problem:
There should be contact between the rear wall of the housing and the brass plate in the middle of the rear...
Here is the gauge itself, after removing the dial, front view:
And here again, with instructions, what goes where:
But first we´re going to measure the resistances of the two coils:
It is the coil that is connected to the housing and the left connector (=the right one on this front view!) It should have a value between 40 to 55 Ohms.
It is the one that is soldered to the two connectors.
It should have a value between 30 and 32 Ohms, the same we´ve measured before.
Here´s again what has to be soldered where:
Coil one (the left one in the pic) has it´s rear wire soldered to the connector in the middle, on the rear brass sheet.
The front wire is soldered to the right connector, together with the right front wire of coil two.
Coil two (the right one in the pic) has it´s left wire soldered to the left connector.
Additionally, I solder the threaded bolt and the loop of the connectors together to secure a good and durable contact:
After that, you can secure the threaded bolts with some two component resin or something similar...
Next thing to do is to solder the rivet and the rear brass sheet together for the same reason:
Here´s a pic of the ready soldered gauge, showing the wires connected to the right spots:
Now we can take the measurements again:
Good value, too!
What comes next is additional work. It is not original, but I think it can´t be seen and secures a durable function of the gauge.
It´s up to you if you want to do this:
Solder a piece of wire to the brass plate on the rear:
The other end of the wire is soldered to the inner side of the housing itself:
If you don´t want to add this wire, you just have to clean the rear inner wall of the housing with a file and the rear brass sheet to secure good contact.
the dial goes back on:
Be sure to bend the hand straight, so that it won´t touch the dial or the front glass!
Put the two small insulator washers back on and stick the complete gauge back into the housing.
Be sure not to turn it upside down! The notch of the housing must be at the 6 o´clock position.
Secure the gauge with two new lockwashers and nuts.
Now is the time to measure again:
Value between the two posts is still ok.
And -- TADAAA! --- the value between left post and housing is fine, too. Now the fuel gauge should work just fine for a looooooong time!
All you have to do now is clean dial and glass and lid, and put everything back on.
The rim of the lid gets bent over with a pair of pliers. Then just paint it.
Last thing to do is claen the back of the housing´s outside to secure good grounding to the dashboard and the dashboar clamp.
You see, it´s not hard to make a fuel gauge work again!
My advice here is just for the WWII 6 volt modell, I don´t know if it works for the later types, too.
The grounding problems are the same. The Ohm values should be different, though.
If you have any questions or improvements, please let me know!
Moderators, if you think this is ok, you could make it a sticky.
Hope this helps!
Cheers from Germany,