I think you may find that this model has a non-removable bottom plate which prohibits access from underneath.
A couple of things: I was looking for a baby guide to shock absorber replacements.... everywhere it is said that it is "easy".. but none of the descriptions of the work that I read were complete. So, this is my attempt.
First, our W820 has no bottom plate, so access is possible through the base, contrary to what was written above: BUT, you might not need it.. read below.
The steps are as follows:
1) Open the washer door. Turn off and disconnect the power.
2) Remove the top: To do this, take out the two plastic screw covers on the left and right of the top and undo the screw. (Crosshead). The top can be hinged backwards and then lifted off.
3) Inspect the drum. Push it up and down; if it bounces more to one side then that is probably the location of the faulty shock absorber. It is good practice to replace both shocks at the same time. However in our case a repair man fixed just one ! a year ago and the bouncing showed that the shock on the right was faulty.
3) Remove the washer front panel. You do this as follows:
a) Remove the soap drawer and put it to one side, pulling it forwards and depressing the red plastic lever visible towards the rear of the drawer. This allows it to be slid out.
b) Remove the three star-headed screws holding the soap drawer surround in place (I used Allen screw drivers for this.. not good I know).
c) Open the panel used for draining the machine (front panel, bottom left) and unhook the plastic drain pipe which clips into the door.
d) Remove three 10 mm bolts from the front panel. These are around where the wash door would normally close (I hope you left it open from step 1)
e) The front panel can now be hinged open (hinges on the right) and you should be able to see inside. Take the opportunity to clean up any visible mess.
4) Inspect the shock absorbers. The right hand shock is visible through the bottom right of the front of the machine. It is a metal cylinder about 6" long fixed at an angle. The left shock is visible but hard to access from the front.
5) In our case we only need to replace the shock on the right. You need a 13 mm ring spanner and you can do the removal entirely from the front... without even moving the machine. Undo the bolts at the top and bottom of the shock and pull it out. Inspect it for confirmation of fault. In our case there was NO resistance to movement at all. If it looks to be in good condition then it is probably the other shock causing the problem. In any case replace both.
6) The left-hand shock needs the machine put on its side for access through the base. Put down some cushioning material, blankets, heavy cardboard, etc to protect the sides and gently tip the machine. Ideally this is a two-person activity. If not, be careful! Again, with a 13 mm ring spanner unbolt and replace the faulty shock.
7) How tight should you bolt the shocks.. as tight as you can with one hand. The machine is robust.. but breakages can occur if the ring spanner slips and hits wiring or connectors, so ensure that the spanner is always fully home on the bolt head and wiring pushed out of the way. I protected my hand from spanner slippage by wearing a gardening glove for this part of the operation.
7) Now all we need is to reassemble:
a) First close the front panel and bolt it shut with the three bolts around the door. These take the strain and should be bolted first.
b) Then we put back the three screws holding the surround for the detergent drawer. Don't over tighten.. it just needs to be firm, not rigid.
c) Reattach the drain plug to the door of the access panel (bottom left) and close it.
d) Lastly, replace the top of the machine, attaching the rear of the top first and hinging downwards, and then use the two screws and plastic screw head covers to complete the job.
You should now have a working Miele with several more years left to run.
When we bought our first Miele (in Holland) it had an expected lifetime of 20 years according to the store. It survived for 20 years, surviving moves across 3 countries. We then tried Hotpoint.. total rubbish and it died after 3 years. We are now on our second Miele and it is around 17 years old and, with this repair, working perfectly. Perhaps one more will see us into (and out of) retirement. In the meantime, it is worthwhile keeping these excellent machines in good condition. They are not throw-away!