Good afternoon my name is ***** ***** I will assist you with your query today, I understand you have replaced the brush, can you confirm this spins freely by hand?
What level of suction are you getting?
It sounds like the friction is to great, unfortunately without seeing it I cant really suggest a solution, so will opt out in favour of another engineer.
HI,My name is ***** ***** I will help with your question. The dc25 has a few common problems with the head. The motors do burn out also they have a problem with the cables that supply the power to the motor snap as they enter the ball housing.Would you be looking to repair the motor yourself? Changing the motor in the head is not too difficult it takes me about 15mins. repairing a broken cable is a little more fiddly.