Water pump bearing is the most important part f the auto water pump.Because the high speed of revelution,usually it reaches 9000r/min,it requires the high-load ability of water pump bearing.And only this can guarantee the life of bearing under the high speed revolution.   Becasuse of the limited space,bad operation condition,the water pump bearing should assure the normal revoluation requirement,and the same time can decrease the bearing's ability of load.It is difficulty for the seal of bearings,because the reliability and the wear ability of the bearing will effect the usage of the bearing.Totally,loadng ability,operating seal and operating clearance,are the importand factors effecting the capability of the bearing.