I have an R7000 3/8" drill that will now only work in certain orientations, i.e. upside down and at an angle. I suspect that the carbon brushes are not making contact except when the drill is held just so. I tried clean the rotor that the brushes touch , but that did not change how it performs. The brushes do not look too worn out and they appear to be making contact. Time for new brushes or a new drill?