Ensure the lubrication quantity

It is important to ensure the proper fill quantity of lubrication in order that all contact surfaces are provided with a suitable lubricating film over the operating life. Both over-lubrication and under-lubrication are very harmful. With over-lubrication, there is an increase in the internal friction of the component as excess lubricant is moved through the free space. This results in increased heat generation and then the shorter service life. With under-lubrication, not all contact surfaces are supplied with the proper quantity of lubricant. This may lead to wear and then shorten the bearing service life. 

The purpose of the lubricant is to provide the contact surfaces with a consistent lubricating film, thick enough to prevent metal-to-metal contact. The correct lubricant quantity is determined by the design, operating speeds, reservoir volume, and the extent of sealing or shielding found in the application. http://www.zys-bearings.com/