Fix my overheating drive head Mcculloch Trim Mac 210 Type 1 petrol strimmer?

Is there a bearing at the end of the driveshaft tube on this strimmer and if so how can it be replaced?
The hexagonal nut and threaded stud is very loose and running 'out of true'.
It seems to binding, overheating, melting the plastic cutter hub and stalling the engine on idle.
Thank you