DJI motor grub screw loosening and giving rise to motor failure.

[Rowgerwulff]

Hi,

Don't know whether anyone's seen this failure before, but it could have been nasty if it occurred in the air.

One of the motors would not turn when on the ground (after a period of flying normally). It was clearly getting power, and my first thought was that there was an ESC problem. On examination, the motor can was lifting up, and this was due to the grub screw on the shaft (centre to picture) being loose.

Looking further at the photo, the shaft that the prop fits to is slightly bent - (from one of several earlier crashes ;D) - but the quad has been flying normally for a good long time. Lucky the issue manifested itself on the ground really. I pushed the can/shaft back into place and tightened the grub screw - it seems to be ok. I've since looked at the other motors, and one of the screws could be tightened further. Upshot is that anyone else who's had a few bumps would be well advised to have a look too......

Cheers RWF

[Charliewalker]

When I built a Depron Lancaster (not FPV) with no undercart every time it landed one or more of the props would catch the ground & bend the shaft which I'd just tweek back into position, but then being slightly out of  ballance they would vibrate enough to loosen the grub screws every time untill I ended up epoxying them in.
   The point I 'm trying to make is to keep a check things stay ballanced or it will cause more problems!
   

[Rowgerwulff]

Good advice. I've been back out and had a look.

I've done quite a few hours without any issue and with nice video and no jello - but possibly a new motor reqd to be on safe side.

[MarkLincs]

Er use blue thread lock :)

Or if that's not good enough use red :)

[Rowgerwulff]

Yep fair dos- but not sure how long it's been like that - just put it up and back down - haven't properly test flown and looked at gopro footage......