There's a video on YouTube that shows how to change washing machine brushes - it's filmed on a bench probably because they couldn't get a camera inside the machine....
http://www.youtube.com/watch?v=0GmtRBiXLFc
However, even though I know very little about washing machines I can't agree with the "brushes" diagnosis.
Before the machine spins it needs to empty the water - spinning with water in the drum might be difficult for the machine to cope with. You also say that the timer dial is not advancing - that may be because the machine's logic is waiting for the drain pump to empty the machine - when empty the timer can advance and then spinning can begin.
My guess is a defective drain pump rather than the brushes - which is a shame because brushes are easier and cheaper than a drain pump.
Good luck...
Peccavi
August 2009