# Farmall 400 change from 6 Volt to 12 Volt



## dakota_dj (Sep 17, 2003)

I have a 1956 Farmall 400. I would like to change the charging system over to 12 volts. Has anyone done this? What all is involved and what parts are needed?
Thank you,


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## bear (Oct 20, 2003)

tim it is quite an easy conversion. you will need a resistor in the wire to the positive side of the coil. go to auto parts store and ask for a dodge coil resistor. as for the charging system there are 2 ways to handle that you can set the on the old style voltage regulator or if you will be using the tractor a lot i would recomend putting on a delco alternator off of any 70's through mid 80's gm product. and of course changing your lights and battery.


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## Bigdog (Sep 18, 2003)

Check this link for wiring diagrams for 12 volt conversion.

http://albums.photo.epson.com/j/AlbumIndex?u=4001561&a=30065733&f=0


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## slipshod (Sep 19, 2003)

*Just Wondering?*

Why do you want to convert the tractor to 12 volt? Are you having problems or is it just something you want to do?


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## FLH69 (Apr 29, 2004)

If you do change it over to 12 volts you may also want to have your starter rewound for 12 volts. The 6 volt starter will work but if the motor is hard to start and if you spin the motor over excessively, it will over heat pretty quickly.


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## dakota_dj (Sep 17, 2003)

I have been having trouble with the 6 volt turning the engine fast enough to start. I have heard of people switching over too 12 volt and it will spin the engine faster. I think that will help out with my tractor.
Thanks for the replys and links.


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## Bigdog (Sep 18, 2003)

Check your cables and connections. Are the cables 6 volt heavy gauge cables or have they been replaced by lighter gauge 12 volt cables? Also check the post connections and ground. Crank the motor over for several seconds and then feel along the cables and at the connections. If you feel warmth, you are losing efficiency from resistance either due to cables that are too light or connections that are bad.


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## FLH69 (Apr 29, 2004)

Tim,
I have an old Case VAC that had a 6 volt positive grounded system that I had the same problem with, even with a brand new 6 volt battery. I switched it over to 12 volts and that sucker spins over now. I had my starter redone for 12 volts although you don't have to do that. Just don't spin it over for an excessive length of time without stopping to let the starter cool down. I did it for peace of mind I guess. 
I used an alternator from a GM that had an internal voltage regulator. Have had no starting problems since.


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## dakota_dj (Sep 17, 2003)

Bigdog
I have checked the cables and wiring. All seems to be OK. 

FLH69
I found a company that sells kits for the Farmall 400. Kit includes the Alternator, (GM Internal regulator) all brackets, wiring harness, coil that does not use an external resister and a volt gauge for $199.00. I am thinking about ordering one of these kits instead of trying to piece all the parts together and fabricate the brackets.

Thanks for the responses.


Tim


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## parts man (Sep 24, 2003)

You will still need a resister as the pionts will burn on 12 Volts. If you use a 12V coil, the resister goes between the coil and points, with a 6V coil, the resister goes between the ignition switch and the coil.


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## FLH69 (Apr 29, 2004)

Parts Man is right about the resistor unless the coil that comes in the kit has an internal resistor. You may want to check with this company to see if it does. I did not have that much money in mine but you are right, I had to make brackets, change the pulley on the alternator because of the different belt width, etc. Wasn't really too bad but if you don't want the hassle, the kit would be the way to go.
Good luck.


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## Ace Schrunk (Sep 15, 2003)

*6v to 12v*

dakota don't be to suprised if going to 12V does not help much. I changed 6v to 12v back in the 60's many times some times it helped and some time not. Did a 400 once and could not tell the difference.


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## Chris (Sep 15, 2003)

Welcome back Ace ---- long time there my friend. 
hope to see you here more often! 

Andy ----

:homereat:


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## dakota_dj (Sep 17, 2003)

:bigusa:
Finally got around to switching my 400 over to 12 volts. I used a kit from Genesse Products. The conversion went without any problems. The kit had everything in it to do the job. No more charging problems.

Tim

:ride:


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## parts man (Sep 24, 2003)

Tim, glad you got it sorted out!:thumbsup:


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## bear (Oct 20, 2003)

glad to here things went well tim


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## dakota_dj (Sep 17, 2003)

Everything is working fine on the conversion except for the light switch. I changed the bulbs to 12 volt, but left the original headlight switch installed. The lights are working, but the fuse holder get hot, has not blown the fuse but there was a little smoke coming from behind the dash panel. I am guessing that I will have to change the switch. Does anyone have any experience or advice on the original switch?

Thank you,

Tim:argh:


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## parts man (Sep 24, 2003)

Sorry Tim, I have no experience there, we switch all our Farmalls back to 6V, and put in original switches if they've been replaced.:lmao:


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## TDK (Feb 8, 2004)

Does the fuse only get hot when lights are on "dim" ? If this is the case it's probably the resistor coil on the switch. Seems the coils sometimes(or maybe always) can't take the 12 volts. You could replace with a 12V switch. The 350,400,450 diesels were 12V systems, although I don't know if you can buy new ones. Another idea is, moving wire from "low beam" screw on back of switch to the "hi beam" screw. By doing this you'll have "bright lights only" in both positions of switch. I've done it this way before, low beams are not that useful anyway and no one will know the difference, except you. Incendentally, the part # for a 12V switch is 363131R91, if you decide to go this route. Good Luck!


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## dakota_dj (Sep 17, 2003)

:spinsmile 
TDK

Thank you for the info. I will rewire the switch and see if that takes care of the problem. 

:thumbsup: Tim


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## dakota_dj (Sep 17, 2003)

TDK

Update on Light Switch. 
I decided to change the switch to a 12 volt switch from a 400 diesel instead of switching the low beam terminal to the high beam terminal. The part number 363131R91 has been changed to 371465R91. The new switch is a 3 position switch instead of 2 position. It has low beam, high beam and high beam with the rear light position. All lights are working correctly.

Thank you,


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## TDK (Feb 8, 2004)

Thanks for the new part number info! Does your original knob fit new switch?


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## dakota_dj (Sep 17, 2003)

TDK

The new switch comes with the knob. I tried the original knob on the new switch. The orignal knob will work with the new switch.

Tim


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## BLUTE (Oct 27, 2012)

I would like to do the same thing on a 1947 farmall A. What do I need to do on that one?


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## warren (Jul 23, 2015)

I went through two coils in a little over a year in my 12 v converted 1953 jubilee. Just popped one yesterday. Turns out I need a coil with an internal resistor. Anyway, picked one up and she fired right up.


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