I have a Major. It originally hade two 6 volt bateries hooked in series. So it made 12 volts. I use one 12 volt now and it works fine. I dont have lites on mine so I run positive hot and negetive ground. Same as any new battery comes. Fordson used positive ground. A starter dosent care which way it is hooked. Its works fine.
Ken
August 2008
I've never seen a 6 volt diesel tractor, but to be on the safe side, see if you can find any voltage markings on the starter motor, dynamo, voltage regulator or even light bulbs. You will get a replacement battery - a friendly motor factor will help you out if you can give him dimensions of the battery cradle. Maybe take out a subscription to Classic Tractor magazine? Cheers!