Yep - I broke both of mine the last time I cleaned mine getting the impeller out. Seems to still work fine without them though. If you refer to the following Red Sea parts image of the shaft/magnet, I believe the circled portion is the washer (I'm going off memory here as I disassembled my ReefWaves about a month and a half ago and I can't take them out right now to verify). Hope this is somewhat helpful for you.