I had a similar thing occur a couple of months ago. I called rotovac and they said it must be the power cord so i cut the old cord at about 12 inches and installed a male plug so i could use an extension cord this is what they told me to do. It still had the problem. I checked the brushes and they were good. I noticed that when the curly cord moved the power would cut out. it had developed a break in the wire, close to where the wires enter the motor. I immediately ordered a new curly cord. meanwhile, I wanted to use my 360 that afternoon so i shortened the curly cord thereby removing the trouble area, there were two connectors at the motor end that i had to cut off and splice on. 30 minutes and I was back in business and it still works today, I have a new curly cord on hand to install when I get around to it ( never). By the way my old power cord had done the twisted trick, my new set up features a black farm extension cord that far outperforms the one that came on the 360 originally.
