I've been working my "vintage" Waring 11-298 blender hard for the past 3 years since I received it at a garage sale for free (I refused to make an offer, and the lady just said I could have it).
However, one day I was blending a smoothie and the blade assembly came loose from the base of the pitcher. I noticed some unusual vibration, the blending action was not working like it should, and on top of that, the contents started leaking out the bottom. It was time to give this blender some maintenance.
First, using all the socket extensions available, I unscrewed the blade. Then, not pictured, unscrewing the bushing assembly with pliers.