I have read so many stories about the problems people have had with the loss of suction in their DC01 wand. Well I have just had the same.
Owning a hotel for 10 years, I ran 2 of these models, usually repairing them with no difficulty as they are such a simple and versatile machine. The best of the range I think. When I retired I took one with me so mine is probably 20+ years.
Recently I lost power to the machine so, after checking where the cable enters the machine, I found a severed wire. A common problem and after a repair I screwed back the inspection/ access panel just below the on/off switch. That's when the problems started. My hose would not pick up at all; no suction. I used Google and found this site. It has been so useful although even though I tried all the remedies to solve my problem I could not. I virtually stripped stripped the whole machine, cleaned out the dust and fluff, checked the seals etc etc. But no luck. I was at a loss so I thought about it over the days and finally checked the inspection/access panel again. I noticed that everything is a little tight with all the wires inside and the panel was a little proud fron the body. So I rearranged the connectors / wiring a little and managed to screw the panel flush. And Hey Presto that's all it was! It was preventing the cyclone bin from sealing when closed. I hope this story might help certain people who have been scratching their heads after the loss of suction in their wand.