bench grinder

So I have this bench grinder, and on occasion it squeals a bit.. It's nothing special, just a common 6" grinder (Mark 1, says industrial grade & ball bearing, no external means to oil it). It looks easy enough to split it open, but is there anything I can do to it to quiet it down if I did open...

Hey guys! Still at it in the shop/garage... Bought new tool/attachment that I REALLY like! This is a belt grinder with a flat surfacing disk that bolts to a bench grinder on the right side. Has serrated rubber contact wheel for the belt which allows for hollow grinding on my blades with...