Hub/Rotors

[84_chevy]

Hello

I'm looking for some help/advise. I'm trying to remove the front hub/rotors off my 84 4X4 but I don't have the correct special socket for the job. I went to the local parts store and they did have a socket that looked like it might work but the sales guy was not sure if it was the right size or not and neither am I. What they had was a 40mm socket with 4 prongs, is this correct? If this is not the correct tool what size is it and do I need to go to a dealer to find it or should I be able to find something off the shelf?

Secondly if any of you would offer some advice on replacing the front hubs such as torque setting/ tips and trick or any unforeseen problem I might run into that would be great. This is my first attempt at messing around with hubs and bearing so any help would be appreciated.

Thanks