The pieces of the air motor, the bearings were filled with lubriplate just to make sure no other junk got in 'em on the way home. Brass endplates, about 1/4" thick, steel bore lined with something. Kind of resembles babbitt. Six rotor vanes, plastic, and look brand new. The rotor shaft is actually hollow down the center. Vents excess grease from the rear bearing through into the hammer housing. Those bearings sounded like crap when I took it apart. I knocked off the shields and cleaned them out. For some reason I've found small aluminum flakes throughout this gun, and some were even inside of the bearings. But after cleaning them up all looked OK, so I'm going to put it back together with the original bearings and see if they last. Eventually I intend to add a couple of grease fittings to the housing so I can maintain the bearings without tearing the gun down.