I assume that you are referring to the spanner size required, rather than the thread details. It may not be correct for your vehicle, but on my 1990 Talbot Express (Peugeot J5), I used a 41mm 3/4" drive socket. (I still have the socket.)
You will need to remove the axle cap, which operation is not as simple as it sounds. The official Peugeot manual showed a special set of tongs or large pliers as a special tool. My method was to make two shallow (bursting) hacksaw slots in the cap, and lever out with a large screwdriver. Slots were filled with solder, enabling the caps to be reused.