You won't......if the brushes are worn out, then it's deemed to be at the end of its life.Probabl only cost you around £40 new, so in reality you need to buy a new machine. Tel me....why is it that because it's a bit of machinery people expect to repair it for peanuts- yet pend £40 quid on a kettle and after three or five years when it goes wrong they bin it????
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix hedge trimmers.