Ratchet noise, beater will not turn, belt not broken, in carpet mode the Dyson d07 makes huge ratchet noise and the belt will not turn the beater brush.

Ok, so I had the same ratching noise and took the advice of many sites directing me to clean the brush. But like most I cleaned the brush and the noise continues and the brush does not spin. Reluctant to take it to get serviced I dug a little deeper and now it works just fine. This is what you need to do as removing any hair from just the brush part will not be enough.
Remove the entire brush bar from the bottom of the Dyson, this means pulling the bar out of the drive belt. This is not to difficult just use a little muscle as the belt will stretch. Once the bar is out grasp hold of the two plastic end caps on the brush bar which the brush bar actual spins in. These two caps are connected by a slim metal rod which runs through the brush bar. Place one hand on each side and begin to twist and pull until one of the caps comes off. Once the cap is off of the one side you can pull the other cap from the other side through the brush bar as this cap will be the one attached to the slim bar I mentioned above. If like mine you will see a ton of hair wrapped around these caps and inside the ends of the brush bar. Clean them out as best as possible.
After you clean it out, run the cap with the rod back through the brush bar, attach the other cap and twist and push together. Make sure the caps lineup which each other just like they were when you pulled it out. You'll notice how much more freely the brush bar spins between the two caps then before you cleaned it. Now, pull on the drive belt and feed the brush bar back through and attach as it was to begin with. This did the trick for me.

Exact same problem w/Dyson vac - horrible rachet noise and beater bar not working, even after cleaning all threads & hair from brush & around the belt. Taking apart the beater bar assembly from the ends and cleaning all accumulated dust took less than 5 minutes (OK, add another 5 to get the bar back under the belt) and my Dyson is working like new again! **Thanks glenssmailst.** This is when I love the internet.

Refer to glenssmailst solution - here was my experience:
correct solution to the correct problem - it did turn out that the ends of my beater bar were compacted with dust. Use caution however in removing the ends as I pulled and twisted and ended up cracking the end in half. Once that had happened however, I proceeded to clean out from that cracked end without trying to remove other half or other end - and was successful. The way I did it was to put the vac upright, while bottom was still disassembled, and use the narrow hose attachment to suction out the beater bar assembly while rotating the broken end. It only took a few minutes to get it to the point where it was easy to spin. I then proceeded to wash the broken end pieces with dish soap, dry with hair dryer, and use a few drops of crazy glue to glue the broken piece back on. Since it is well wedged into the assemble it doesn't really take any stress. Just be careful to not hit it while getting the beater bar back under the belt. Turned machine back on and working perfectly. I would say this solution is worth the risk, as a replacement beater bar is only $14.99 online, and mine is working fine glued. A lot cheaper and quicker than taking it to a shop for $50 or more. Good Luck. Nan

Thank you so much for posting this! I will tell you I had tons of hair and carpet threads wrapped around the brush bar from my dog having a frantic moment on 4th of July (yes.... she ripped up some carpet by the garage door) we cleaned the brush bar off and it was still not spinning. It was also making that horrible ratcheting noise. We removed the entire bar and realigned the belt..... walla...... all is working wonderfully!