You need to start by stripping the unit down to its motor housing.
From there onwards you need to remove the wheels. On some sites you are told you lever off the wheels with a large screwdriver. However, if you have coloured inserts in the wheel centres of your appliance, then you need to remove these as they lock the wheels onto the spigots.
I found the easiest way of removal is by inserting the short right angled pointed end of a scriber in the small gap around the insert, and pushing the point of the scriber into the material. When you have a sufficient grip on the insert you need to apply a steady pull and it will come out. You can then lever off the wheel very easily with a large screwdriver. The rest of the stripdown is easy as it only involves 5 torx (T15) screws (2 on either side and 1 on the top).
Hope this helps,
David Wright
David Wright - Colchester, November 2007