dyson DC05 loss of suction

My Dyson DC05 is suffering from loss of suction. I have followed all on line instructions that I can find. I have checked the hose for both blockages and holes. I have checked and washed the filters, I have checked all the seals and can’t see any defects. The motor sounds ok and there is no smell. The air is coming out of the vent at the top of the dust collector and if I put my hand over it I can get dust to be picked up but the suction is not strong enough to get it completely into the dust collector, it gets stuck in the top of the collector and then starts to block the hose. Also I don’t think I should be blocking the vent! Finally I had one more go and I brushed the cylinder inside the dust collector and cleared out a whole lot of dust and now it works again! Hurray! 😀 😀