1959 Ford 641

Good evening all.
I have a 1959 Ford 641 Workmaster. I bought it about 3 years ago. It is still 6 volt system with generator.
It has ran and started great the whole time I have owned it. All the wiring looks to be in great shape. Last year the fuel gauge stopped working. I replaced it and the sending unit. It shows full or empty depending on how I wire it. I gave up on it.
The battery failed last week.
With the help of you guys here I have discovered the battery had been put in as a negative ground by the previous owner. I have been bench testing the fuel gauge and sending unit with the new battery. I can get it to work if I touch the sending unit to the positive post with the ground wire on the positive post and the "B" wire on the negative post. This is with a new battery that has not been reverse charged.

If I drain the battery and reverse charge will the fuel gauge work?

I believe I will have to reverse the generator polarity. How do I do that?

Will the coil wires need to be reversed?

Sounds like the gauge is made to work with a positive ground system.

All you would need to do is install the battery positive ground, don't try to reverse charge it.

For a positive ground system, the coil should wire =+ to the distributor, - to the ignition switch.

You will need to polarize the generator before starting the engine Here's where it gets confusing, I don't know if your generator is internally grounded field, or externally grounded. Some of the Ford experts can probably tell you, but it does make a difference.

If it has an amp meter, it may read backward if it was changed by the previous owner. If it does, reverse the wires.
Polarizing a Generator

Why would you want to drain the battery and reverse charge it?

I believe your model was positive ground on the 6 volt tractors. The 12 volt ones were negative ground. Install the battery as positive ground, polarize the generator before you try to start the tractor. To polarize a Ford type ("B" system) generator remove the field wire from its terminal on the regulator and momentarily touch the field wire to the battery terminal of the regulator. You will get a spark when you do this. Do this before you start the tractor.

Also before starting the engine, check the wiring at the coil. The wire from the switch should be connected to the negative (-) terminal of the coil and the coil's positive (+) terminal should have the wire going to the distributor connected to it.

If the battery was installed as negative ground before, you will need to reverse the ammeter wiring as well or it will show discharge when it is charging.

Draining a battery then charging it back up backwards will only do one thing for you and that is the make you buy a new battery because doing that kills a battery

(quoted from post at 16:03:25 09/19/18) Sounds like the gauge is made to work with a positive ground system.

All you would need to do is install the battery positive ground, don't try to reverse charge it.

For a positive ground system, the coil should wire =+ to the distributor, - to the ignition switch.

You will need to polarize the generator before starting the engine Here's where it gets confusing, I don't know if your generator is internally grounded field, or externally grounded. Some of the Ford experts can probably tell you, but it does make a difference.

If it has an amp meter, it may read backward if it was changed by the previous owner. If it does, reverse the wires.
Polarizing a Generator

Click to expand...

Thank you

(quoted from post at 16:06:22 09/19/18) Why would you want to drain the battery and reverse charge it?

I believe your model was positive ground on the 6 volt tractors. The 12 volt ones were negative ground. Install the battery as positive ground, polarize the generator before you try to start the tractor. To polarize a Ford type ("B" system) generator remove the field wire from its terminal on the regulator and momentarily touch the field wire to the battery terminal of the regulator. You will get a spark when you do this. Do this before you start the tractor.

Also before starting the engine, check the wiring at the coil. The wire from the switch should be connected to the negative (-) terminal of the coil and the coil's positive (+) terminal should have the wire going to the distributor connected to it.

If the battery was installed as negative ground before, you will need to reverse the ammeter wiring as well or it will show discharge when it is charging.

Click to expand...

Thank you.
It is my misunderstanding of the positive ground system that made me think it needed charged differently.. :?

(quoted from post at 16:12:18 09/19/18) Draining a battery then charging it back up backwards will only do one thing for you and that is the make you buy a new battery because doing that kills a battery

Click to expand...

Makes sense. Thats why I am asking you guys.

Make sure you have a Ford Autolite generator. If, for some unknown reason, someone put a Delco system on it the polarizing procedure is different.

(quoted from post at 16:36:09 09/19/18) Make sure you have a Ford Autolite generator. If, for some unknown reason, someone put a Delco system on it the polarizing procedure is different.

Click to expand...

Thank you.
Will do.
I think the tractor is all original but will check.
The tractor only had 1350 hours on it. Steering is tight and only surface rust no rot. Would be a great one to restore.

+ ground or - ground both work the same just if + ground it has the + side of the coil going to the distributor and the generator charges it just like it would with as - ground just has to be polarized for which ever ground it is. But if it had an alternator well they need to have the battery hooked up correctly of you will let the smoke out of them the moment the cables are hooked up. 99% of alternators are - ground and about 1% are + ground

[/b]I wanted to thank everyone for their help. I put the new battery in as a positive ground. Then removed the battery and field wire off the voltage regulator. Touched them together for a little spark. It started right up and fuel gauge works now. As far as I can tell it is charging correctly. I had around 6v with the tractor not running. When running and idled up it was around 7v.
And no smoking wires.

Thank you everyone.