How to Rebuild a 2-Speed Electric Swamp Cooler Motor

Unplug the swamp cooler and access the two-speed motor. Unscrew the swamp cooler's back panel with a Phillips screwdriver. The fan blades are attached directly to the motor assembly.

Disconnect the fan blades by loosening the screws or bolts fastening the assembly to the motor. Also, using a socket wrench and socket, disconnect the motor by unfastening the bolts mounting it to the swamp cooler assembly. Take the motor out of the swamp cooler and place it on a level work surface.

Open the motor. Fan motors are self-contained, cylindrical units and different swamp coolers have motors of different specifications. Electric motors are joined with bolts on the end of the casing. Remove the bolts with a socket wrench and socket and open the motor. Electric motor rebuilds commonly involve changing the brushes as well as inspecting and replacing the end bearing and bushing.

Replace the brushes. Electric motors normally have two carbon brushes to charge the motor. Brushes are connected to the turning armature and remain fixed while the armature rotates. One brush has a black wire, the other one, red, identifying positive and negative. Cut and remove the brushes with wire cutters and install the new ones. Put the brushes in place and solder them, sealing the connection. Plug in the soldering iron, allow it to heat up and place the solder and iron to the connecting wires. A drop of solder melts onto the wire sealing the connection. Allow the solder to cool for a few minutes before replacing the new brushes and immediately wipe up any extra solder.

Replace the bushing and bearing. Using the proper bushing and bearing for your swamp cooler model. Bearings allow the armature to spin freely and the bushing allows the bearing to operate properly. Located at the end of the motor (opposite the fan blades), both are easily removed by hand. Many fan motor bearings have openings to lubricate with oil: Install the openings facing upward so the oil doesn't drip out.

Oil the bearing with SAE 20-weight or a lubricating oil. Bolt the fan motor together, fasten the blade assembly to the front of the motor, then mount the motor back to the bracket inside the swamp cooler. Affix the back plate and operate the swamp cooler.