Not just over worn pads? If not, no they aren.t too bad to do. You do have to remove the hub though, as they are mounted to the rear of the it, and not fited over the studs like most cars. First remove the free wheeling hub. Unbolt end cap first with hub set to 'free'. Ezz it out gently. Therte should be a circlip around the end of the half shaft / stub axle, take it off. Undo bolts that join FWH to hub. Slid it off shaft. Unbend locking washer from over hub nut, big feller in centre of hub. You should now use a very larg socket to undo this, but it can be done gently with a screwdriver / chisle and hammer. There should be a secon nut under the first, undo that to. Now tho whole hub comes off. Change disck, cheack barings while it's all apart, grease everything that needs it, and reasemble. There is probably a torque setting for the hub nut, but i have always gone with do it up as tight as it will go, then back it off one flat / 1 sixth of a turn.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.