Converting the 6-volt John Deere to a 12-volt system is a good idea if you are looking to improve the performance of your Deere. Unless you are hoping to restore your tractor or maintain the original condition, a 12-volt conversion is worth your time for a number of reasons. The agriculture industry converted to a 12-volt standard in the 1950s, therefore 12-volt parts are easy to find. A 6-volt battery has a difficult time cranking the starter in low temperatures and a generator can not charge the battery at idle speed whereas an alternator can.
Remove the negative battery cable from the negative terminal of the 6-volt battery. Remove the positive cable. That order is important to prevent you from getting a shock. Unthread the wing nuts on the cage holding the battery to the mount. Remove the battery.
Unthread the screw that attaches the positive battery cable to the generator. Unthread the screws of the two generator wires and detach the wires. They will hang from the regulator. Unthread the nuts bolting the generator to the generator mount. Take the generator off the mount.
Unthread the screws from the regulator and remove the wires. Unthread the two screws attached to the back of the regulator. Unthread the nuts bolting the regulator to its mount and remove it.
Grind the three mounts off the frame of the John Deere. The 12- volt battery, alternator and regulator will not fit on the 6-volt mounts. Weld the 12-volt mounts in the same places the 6-volt mounts sat. If the regulator is attached to the alternator, you do not need a regulator mount.
Mount the 12-volt battery, alternator and regulator to their respective mounts. Fasten the alternator wires to the regulator, if it is separate from the alternator. Connect the positive battery cable to the alternator, but not the battery. Connect the negative cable to the 12-volt battery's negative terminal.
Remove the light casings from the housings with your screwdriver. Remove the bulbs from the light assemblies by pressing them in and making a 1/8 turn counterclockwise. Remove the light assemblies with your screwdriver. Replace the light assemblies with the 12-volt assemblies and do the same for the bulbs. Fasten the light casings on with screws.
Attach the positive battery cable to the 12-volt's positive terminal.