Hi,
If you are just changing the u-joint you can leave the big nut on the axle tight. take out the four bolts (from the backside) that hold the hub/bearing to the knuckle. you can pull out the hub/bearing with axle shaft attached, change universal joint and reinstall. that way you don't change the preload on the bearing and less chance of the bearing "coming apart" during removal. This has worked well for me many times, might give it a shot.
Dave