I rebuilt my pump and I am an idiot. So go ahead and have at it. There are plenty of videos about this but I used this guy's YouTube post. Pump rebuild videoThe only hard part is fabricating two clips to hold the brushes away while you drop the armature back in. He used paper clips, I used baling wire. Be sure to mark the parts for re-orientation later. Very important!!! I also cleaned up the commutator which was very dirty. The small O-ring that separates the reservoir from the motor leaked, contaminating the entire motor. Also be careful not to misplace the little tiny balls and clean the cavity well. The pump rebuild kit that is available from many places contains two new balls and all the O-rings, seals, along with a new reservoir plug. Mine even had three new rubber mounting feet. Pump rebuild kit