Bearing are one of the most widely used elements in rotating shaft systems with great risk of failure that can affect the systems. There are two broad types of bearings used in rotating shaft system: sleeve bearings or journal bearings and rolling element bearings. Split sleeve bearings are used for application where it is necessary to remove a cap for servicing or replacing bearing. Proper clearance between the shaft and the bearing is necessary to avoid vibration or loss of concentric orbit. The performance of rotating shaft system is very dependent on vibration generated by bearings. The use of vibration signal analysis is one of the most reliable measurement for this purpose. The main objective of the present study is experimentally to investigate the role of bearing clearance that is a critical parameter affecting dynamic characteristics of rotating shaft systems. The vertical bearing clearance through introduction of additional shims is operand to simulate a loose -worn- split sleeve bearing. Wear is responsible for many problems and large cost in rotating shaft system. Three different clearances configurations using shims have been tested. The results showed that a worn bearing will have a significant influence on the stability of rotating shaft system.