I have a WD4070 and went to replace the filter today. I unscrewed the white nut and took off the filter. I opened the new filter I bought at the store today (the shortened 3 layer fine dust filter) and it is different than the one that originally came in the machine. The filter originally on the vac has a gasket glued to the filter, not a separate filter plate. The filter I purchased is just a plain filter- no gasket or plate. ???
And yes, the filter and the gasket are absolutely attached. They are glued together. I even ended up ripping the gasket trying to remove it from the filter because it is just some sort of flimsy foam rubber type of material.
Of course, it didn't come with an owners manual and there isn't one available online. Any ideas?