Well, first off, smoke of that nature is not a good thing. The brushes do not look bad to me form the pictures provided. However, if they ever got lubricated with oil or anything, that isn't in their best interest and can cause smoking. Looking over your pictures, I think there is an error in the wiring that was done when the e-unit was removed.
Try this on for size:
Note, the junction where a yellow, blue, and black wire come together is NOT the screw terminal shown below. It can be a wire nut, solder joint (covered with electrical tape), or whatever you are able to come up with.
