Buy new bearings and replace em. If it is a good motor it is worth replacing them it can be a pain if you don't have a proper way of pressing them out. This place sells quality bearing and they have a chart for different motors to get the correct size. If you don't have a way of measuring the ID OD of the bearings. http://www.bocabearings.com/bearing-...motor-bearings
Check the Magnets to make sure they did not come loose, if they did, you can glue them back in with Epoxy or Med CA, make sure they dont get turned around, mark them with a felt pen on one side. also check the motor can, it could have gotten bent, if it is bent, time to get a new motor and save the magnets for canopy hold downs, Hope that helps, Chellie
I may be getting Older, But I Refuse to grow Up I am Having to much Fun to Grow Up LOL
It could also be the actual bell and/or stator mount that is bent, this could case the stator to rub on the magnets which would explain the grinding noise. Check the motor and make sure that the bell/rotor part (the part that spins) is straight and true against the fixed part of the motor, check the gap between the back of the rotor and the fixed part and make sure it's the same width all round the motor.
The other points (bearings and magnets) are worth checking but bearings would not normally cause bad vibration unless the damage was extreme.
The other thing to check is the actual prop adapter, this is quite likely to have been bent in the crash.