How to Install a New Shaft on a Swamp Cooler

Turn off the electrical circuit for the cooler at the breaker panel or by unplugging an electrical cord that provides power to the unit. Remove the covers and cooling pads from each side of the cooler.

Loosen the motor-mount bolts at the base of the fan motor with a socket and ratchet. Slide the motor toward the fan pulley to slacken the belt. Remove the belt.

Grip the outer rim of the fan with one hand as you loosen and remove the fan-pulley bolt with the socket and ratchet. Pull the pulley off the drive-end of the shaft.

Loosen the fixing bolts at the bearing mounts on each side of the fan with a hex wrench. Lift the shaft out of the mounts. Pull the fan out of the fan shroud and the cooler from either side.

Place the fan on a workbench. Loosen and remove the recessed keepers at the outer rim of each bearing with a small hex wrench. Slide the bearings off the shaft.

Spray lubricant inside the shaft housings at each end of the fan.

Position one end of the fan flat against the edge of the workbench so the end of the shaft rests on top of the bench. Tap the outer end of the shaft with a hammer to unseat it from the shaft housing. Remove the shaft by hand. If necessary, attach locking pliers onto one end of the shaft, grip the fan and rotate the pliers to unseat the shaft.

Install the new shaft through the housings and center it each way in the fan. Slide a new bearing onto each end of the shaft. Align each bearing with the machined flat spots on the shaft. Secure the bearings by tightening the recessed keepers against the flat spots with the hex wrench.

Reinstall the fan by repeating steps 1 through 4 in reverse, making sure the threaded port where the pulley attaches at the drive-end of the shaft is at the same side as the motor.