Make sure that the electric motor is disconnected from the power supply before you replace the bearings. Locate the screws or bolts around the edge of the motor that keep the two halves of the casing together. Expect to find four or six screws or bolts.
Remove the screws or bolts using a screwdriver or wrench. Put the screws or bolts somewhere safe.
Use a flat head screwdriver and gently pry the two halves of the motor casing apart. Lift off the top half of the motor casing and lay it next to the bottom half. You can’t separate the two halves completely, because there is internal wiring connecting the halves.
Hold one end of the armature using one hand and hold the other end with your other hand. Lift the armature directly upward and put it to one side. The armature is the central spindle that has wire winding around the central part. As you lift the armature upward, expect the brushes that touch the commutator at the front of the armature to spring together.
Locate the bearings on the front and back of the two halves of the motor casing. There are a total of four bearings. Use a small flat head screwdriver and gently pry out the bearings. Be careful not to scratch the area where they are seated.
Wipe the sleeves where the bearings fit using a clean dry cloth. Rub the sleeves using a small amount of engine oil. Wipe off any excess. The oil makes it easier to fit the new bearings.
Put the new bearings into the sleeves on the motor casing. Gently push them into place until they are seated tightly.
Push the two motor brushes apart. Use your fingers to do this and then replace the armature onto the bottom half of the motor casing. As the armature sits on the bearings, release the brushes so they connect with the commutator.
Rotate the armature around carefully so it beds in the lower brushes. Replace the top half of the motor casing. Replace the screws or bolts and tighten them. Rotate the armature several times using your fingers. This beds in all the brushes. Reconnect the electricity supply. Turn on the electric motor.