so i binned my 5inch pretty hard into a concrete wall last weekend, was pushing through a gap too fast and just miscalculated the angle. anyway one of the motors is making this horrible grinding noise when i spin it by hand and there's obvious wobble in the bell. pretty sure the bearing is toast at minimum but im wondering if i should bother opening it up to check or just swap the whole motor out.

the thing is when i plug in the battery and arm it, that corner just doesn't spin at all. like nothing. the other three spin fine. i've already reseated the ESC connectors and checked the solder joints on the pads which all look okay to me but i'm not super experienced with board-level stuff. could this be the ESC going bad from the crash impact rather than purely a motor issue, or does the grinding + wobble basically confirm motor is dead and that's why the ESC isn't seeing it spin

running a 45amp 4in1 ESC setup btw, the stack took the hit on the bottom plate but nothing looks cracked

if you've got physical wobble in the bell and grinding on manual spin then yeah the motor is cooked, bearings are definitely gone and probably bent shaft too depending on how hard you hit. the ESC not driving it is almost certainly a protection thing ? most modern 4in1s will cut output to a phase if it detects a stall or shorts through a damaged winding. swap the motor first before you start assuming ESC damage.

that said if you want to be sure before ordering parts, desolder the motor and use a multimeter to check resistance across each pair of leads. if one pair reads significantly different from the others you've got a damaged winding. you can also just swap in a known good motor temporarily to confirm the ESC output is actually working.

had almost the exact same thing happen to me with my toothpick build, slammed it into a fence post and one corner went completely dead. turned out to be the motor in my case, the shaft was visibly bent when i looked close. just replaced it and everything came back fine. i wouldnt overthink the ESC unless the motor swap doesnt fix it