The most common cause of pump bearing failure is in fact not fatigue. Thrust bearings for centrifugal pumps can sometimes fail before the theoretical life due to the following:
Contamination: this occurs from three potential sources; fluids, metallic particles and dirt or dust. If the bearing is kept in its original packaging and is not exposed to the elements until installed, you reduce the chances of exposure to dust or dirt. Also, it is imperative that you do not contaminate the bearing while handling it by having dirty or greasy hands.
Inadequate or ineffective lubrication: proper lubrication of the bearing avoids direct metal to metal contact and reduces friction, abrasion, rust and corrosion as well as prolongs the service life. However, inadequate or ineffective lubrication can cause bearing failure and increase heat and friction generated. Most lubrication failures occur due to the wrong lubricant being used, too little or too much grease/oil and contamination of the grease/oil by objects or water.
Incorrect mounting or installation: during the mounting and installation it is crucial that operators avoid misalignment or shaft deflection, and are aware of radial internal clearance.
Operational stress and bearing selection: if the load becomes to high, overloading and early fatigue may follow. If the load is too low, skidding and improper loading of the rolling elements may occur. The first sign of these issues is generally unusual noises and/or increased temperatures.
Environmental influence: lubrication and installation failures will occur if the operating environment is not considered. These environmental influences can include:
dust and dirt contaminating the bearing
aggressive media or water
ambient operating temperature
current passage or electrolyte corrosion
