What to do, well, if your not in a rush and don't need an instant fix, try painting a modicum of white 'PVA' glue carefully on the cleaned ends of the motor, refit the motor in cleaned mounts and leave it to dry for 24 hours in situe.
The motor is quite firm and doesn't move when it gets hot. I'm running a couple of models at the moment which have recently had this treatment and as yet they haven't let me down.