We experience a problem with one of our ID Fans. The machine train is Motor - Oil Flex - Centerhung Fan. The Fan bearings are showing high vibration. Seems like a clearance issue. The clearance between the shaft and the bearing is 2.5 mm. One of the expert suggest for a shaft repair. Shaft OD at present is 179.30mm. Required is 180 mm. Shaft repair is costly and we need a second opinion. Did any of you experience similar problems? Is there any alternative? The vibration signature is attached.