Today I was vacuuming with my Oreck XL 100C, when I noticed the motor slowing down, returning to normal speed for a brief instant, then continuing to run at half speed. While doing such, the commutator arcs like crazy. I took the machine apart and found that the brushes had plenty of life left. I know at Oreck when such a problem occurs, we'd just tell the customer they need a new motor. Does anybody with a better working knowledge of motors know what is happening? I know the cleaner is approximately 25 years old, but considering the condition it's in, and the light use its had, this shouldn't have happened. I hate like hell to replace the motor, as the new 4-amp motors are noisy as anything. I'd like to keep it as it came from the factory. Any suggestions?