There are two possible sources of the leak.
One is around the O ring which seals between the mounting shaft unit and the bottom of the pan. It has an ID of about 24mm with a square cross section of about 1mm. I have a new on here which you can have if you cannot obtain a replacement locally.
The other possible leak is between the drive shaft itself and its rubber seal. If so a full replacement is necessary. I replaced the whole mounting shaft unit a few years ago. It was not leaking. The Matsushita part number is ADA13A101 with an alternate part Co. of 031 757 0075 2. I still have the old unit which you can have at no charge. This is the complete unit including the O ring etc I'm in Nova Scotia, Canada.
My unit is 15 years old and has made well over 2000 loaves.
johncam
April 2008