Its a biotch especially if they have never been done before.. If you have a bearing puller it will make life alot easier..but if you use a flathead screw driver and a hammer ( which works ) it will take longer.. It took me almost 3 hours to do mine, but thats becuase the one bearing was seized and turned out to be a nightmare.. As long as your bearings are not seized to the carrier it shouldnt be that bad..But it will require alot of banging..and prepare to wreck a flat head..so use an older crapy one and not one of your good ones..Also use a piece of wood or a brass punch if you have one on the end of the axle when you are hiting it out of the carrier..you dont want to damage the end of the threads..
Good luck..
Now Gettt errrrr donee!!