Replacing the rear bearings is slightly harder than doing the front bearings as you have to pop the drive shafts out to access the 4 torx bolts around it. If you have the ability to remove the 4 torx bolts without removing the shafts you may save time but it may not be possible. Pulling the bearings from the drive shafts may be very difficult as well.
The silver disc is the outside of the wheel bearing.
Looking behind it you will see the thread sides of the 4 torx bolts that hold the bearing.
Look around behind the drum where the drive shaft was removed from and remove all 4 torx bolts. Make sure you support the brake housing as it is also held in place with these bolts. If you don't support it, the weight could bend and damaged the hard brake lines.
If you have a problem getting the old bearing unit off, screw the 4 torx bolts a little way into the bearing and hit them in turn with a rubber mallet.
Here is an old and new rear bearing to give you a better idea of the part.
Smart part number Q 0002072V01000000
It is a good idea to apply copper grease to where both parts touch.
This will ensure that the new bearing doesn't seize.
Don't get any of the copper grease in the bearing, it will destroy it.
With the new bearing in place, tighten the torx bolts up to 65Nm.
Replace the drive shafts, brake drum and wheel.
Replace The Front Wheel Bearings
Mod Credit - T1ny and Evilution.
Stretch hub bolt - 0001906V005000000 - 1 per side.
Front bearing hub - 0001870V02300000 - 1 per side.
Remove the centre cap to reveal the centre bolt. There isn't much of a chance that you can remove the caps without damaging them, for the price, don't bother, just lever them off.
Remove the E14 centre bolt (stretch bolt) and slide the wheel hub off.
It should just slide off, if it gets caught, lever, don't pull. (unless you like ball bearings).
What you have left is the dust cover, give this a good clean up as dirt can build
up between this and the brake disc causing a metallic ringing noise.
With that off you reveal the sensor and the axle stub, carefully clean the sensor.
Put the new bearing in place, if it doesn't slide all the way onto the stub, don't force it.
Reinsert a new stretch bolt and tighten to pull the new bearing in. Torque to 120Nm.
Always replace the stretch bolts with new ones when you remove them.
Refitting is the reverse of removal.
Points To Note
Unlike the rear reluctor rings, the front reluctor rings are part of the bearing.
This makes them very easy to change and a lot cheaper than the rears.