Loosen a few self-tapping screws or screws outside the electric drill; open one half of the casing when laying it flat; generally, the structure of the new hand electric drill is semi-embedded, that is, all mechanical and electrical components are installed in the other half of the casing
Carefully remove the carbon brush first, then take off the end of the drill chuck, then gently lift the motor to take out the rotor (do not damage the enameled wire), clean the commutator on the rotor (the one that is in contact with the carbon brush), if it is too dirty Or if the wear is severe, it can be polished with emery cloth and then polished with water sandpaper or metallographic sandpaper until it is bright.
If the front and rear bearings of the rotor are sealed, the outside can be wiped clean. If the seal is broken, it should be replaced in time. Clean the helical pinion in front of the rotor
Wipe the oil inside the casing clean. Clean the helical gear and the bearings (or bushings) on both ends of the drill chuck rod.
Reinstall the removed parts, first install the rotor; then install the helical gear of the drill chuck rod; install the carbon brush, if the carbon brush is shorter than 7-8 mm, it should be replaced in time. The carbon brush should be installed and flattened. Finally, find a little "Mobil" or "Shell" grease and add it between the gear pair and the bearing (or bushing). Tighten the screw and turn it by hand to feel that there is no sticking, then you can test the rotation after powering on.
