Oil The Bearings Regularly
Oiling and inspecting your Swamp Cooler or Evaporative Cooler bearings can save you major headaches and expense. On most of the commonly used Coolers, oiling the bearings is a very simple job. The majority of residential and small commercial models originally come with a bronze bearing. There are no moving parts to these bearings as there are with ball bearings. Bronze bearings are made with a sleeve of bronze inside a steel die-cast housing. The blower shaft spins inside the bronze sleeve. These type of bearings allow for a smooth, low friction motion between the two solid surfaces. The bronze portion of the bearing is generally about 1/8 to 3/16 of an inch thick and is porous for continuous lubrication. You will see an oil cup at the top of the bearing. Open the cup and then drop about 5 – 10 drops of lightweight machine oil into the oil tube. This should be done at least once a year for light Cooler use, or several times a year for heavy use. Even though bronze bearings are relatively inexpensive they are quite durable. Often times, if you oil them regularly and the belt tension is maintained correctly, the bearings will last for the lifetime of your Evaporative Cooler.
Inspect Your Bearings
It is very important that you inspect the bronze sleeve thickness when you are oiling the bearings. As I mentioned earlier, the sleeve of bronze in the bearing is only about 1/8 to 3/16 of an inch thick. The steel blower shaft is continuously spinning within the bronze sleeve. If the steel shaft eventually wears through the bronze sleeve, then you have steel spinning on steel. Steel spinning on steel always makes a loud, high pitched noise somewhat similar to the sound of a loose belt squeal. Once again it is very important that you inspect the thickness of the bronze sleeve. When any part of the bronze sleeve has worn to half of it’s original thickness the bearing should always be changed. If you let the bearing get to the point of steel spinning on steel, you have damaged the blower shaft. When the shaft has been damaged, you will never be able to use a bronze bearing again. The rough shaft will quickly wear through a new bronze bearing. At this point I would recommend that you install a more expensive ball bearing with set screws in the inner race. This will attach the inner race of the bearing to the blower shaft and the shaft damage will not cause any future problems. Also if the ball bearing ever goes out it will never damage the blower shaft.
Changing Your Cooler Bearings
Unlike most other types of blower units Evaporative Coolers are continuously producing moist air which creates rust on the bearings, blower shaft, and pulleys. This often makes it much more difficult to change the bearings. There are two things that I always recommend when you are changing Cooler bearings. Use a penetrating solvent on any parts that are rusted together. This often happens on the blower pulley and shaft, as well as the inner race of a ball bearing and shaft. Even after using a penetrating solvent I have at times had to use a pulley puller to remove the blower pulley. The other recommendation that is very important, you must always sand the rust off of the blower shaft before pulling the blower pulley or bearing. If you do not sand all the rust off the shaft, you will not only have problems removing the pulley and bearing, it will be very difficult to slide the new one onto the shaft. You might also be tempted to use a hammer to drive the new bearing into place, which often can damage the bearing. As you can see, a few pieces of sand cloth to sand the rust off of the shaft will make the job much easier and actually save you time in the long run.