Got an old dyson that has refused to die, until the other day when it has finally given up, sounded and smelt like the brushes, pulled it apart and ran the motor in the vice and there is all hell fury of arcing and sparking from the brushes. Pulled them out but there is still a lot of meat on them which surprised me. Sanded them down a bit so they have a new edge on and cleaned the commutator(?) ring so it has clean metal. Back together and ran it up, same thing. The brush springs didn't feel particularly strong, could that be a problem? A replacement motor is only £15 but has anybody got any other tips to try before I order one?