so i binned my 5inch pretty hard into a concrete wall last week, one of the arms took the hit and the prop obviously shattered but i replaced everything and now motor 3 is making this low grinding sound when i spin it up, not super loud but you can definitely feel it if you put your finger on the stator housing

ive pulled the motor off and checked the bell visually and i cant see any obvious cracks or dents but something is clearly off. the quad flies but it oscillates weirdly on one axis and i think this might be the cause. running 2306 2450kv motors on a 4s setup if that matters

is this definitely a bent shaft or could it be something inside the bearings? dont really want to order a new motor if i can fix it but also dont want to keep flying it if its going to fail mid air

almost certainly bent shaft, the grinding you feel through the housing is the classic sign. if you pull the bell off and roll the shaft on a flat surface you'll see it pretty quick, even a slight bend will be obvious. bearings can also get damaged in a hit like that but usually they feel more crunchy than grindy if that makes sense

honestly at 2306 size its usually not worth trying to press a new shaft in yourself unless you have the right tools, more hassle than its worth. just grab a replacement motor, theyre not that expensive and flying on a damaged motor is just asking for a flyaway or worse

yeah i had something similar happen and i kept flying it thinking it was fine and then the motor just seized up at about 40 meters and the quad dropped straight down into someones garden. not my proudest moment. just replace it, the oscillation alone tells you something is wrong with the thrust output from that motor and your FC is probably fighting it constantly