Smasung B1245S Spins, but not at full speed, time increased to finish?

it spins, but not at the full speed. It sounds like it's trying to work but failing to. The time for the programme incraeses significanlty (1.5hr cycle takes 2-2.5hrs), with last night it wouldn't complete even just a spin cycle (9min programme, got stuck at 7mins). I've removed the brushes, they don't look that worn, will try to replace them to see if that works, any other ideas? Thanks

Darren
October 2009