I have (had) two Kenmore 116 models, a Progressive and and Intuition.
Both are one of the poorest designed vacuums I have seen, and the Centec derived power nozzles are the worst.
The front axles on the power nozzle always pop off, since it is just a rod bent into a "C" with small wheels on it, and a small plastic "lifter" to raise and lower it. Both of the ones I received had them duct taped down.
A power nozzle should be sturdy and these are not. You do not see many plastic pieces for the 116 Kenmore's on ebay for a reason, they break too readily. I received both of them free, since the owners were frustrated with them. (Broken parts & pieces)