Disconnect the negative battery cable from the terminal with a pair of wrenches. Disconnect the positive cable. Pull the battery from the mount by removing the wing nuts on the cage. Remove the 6-volt battery mount by grinding it off the frame of the tractor. Weld the 12-volt mount in its place. Cage the 12-volt battery to the mount.
Detach the two wires from the generator with the screwdriver. Unbolt the generator from the generator mount. Grind the mount from the frame and weld the alternator mount in its place. Bolt the 12-volt alternator generator combination to the mount.
Remove the screws attaching the light covers to the tractor frame. Unscrew the bulbs. Remove the screws attaching the casings to the frame. Replace them with the 12-volt casings, bulbs and covers.
Attach the positive cable on the coil to the alternator. Attach the positive cable to the alternator, then to the positive battery terminal. Attach the negative cable to the negative battery terminal.