Completing the great Roomba 531 ("R2") shakedown today, after installing new brushes and a battery, poor R2 would run for a few minutes and then complain about needing the brush cages emptied of debris.But there was no debris.The real problem? Dirt caked inside the gearbox on the sweeper deck. Pulled it apart, cleaned it up, lubricated the axles and gears ... good as new!(and runs for the full battery again!)