Does removing the front brake rotor on a 2008 Mazda5 require removing the large nut in the middle of the hub?

 

No. Just remove the caliper, pads, caliper carrier and the rotor will be secured with one or two posidrive or torx screws. You may need to encourage the rotor to come off with a hammer. Clean up the hub face with a wire brush and remove all rust before fitting the new rotor without any grease on the mating surfaces.

 

I came across this while doing a search for myself. Haven't had to use as of yet to see how accurate the info is, but it seems pretty straight forward

http://www.wildweasel.ca/HowTo/Auto/...keInstall.aspx

 

Looks a good guide to me - same as on my Ford. I assume you are changing pads as well.

Not a difficult job but dont do it just on a jack, stick an axle stand underneath and you dont need to let the parking brake off if doing the fronts. A claiper wind back tool is useful especially when doing the back ones