What would make all 4 of my Metco Idler bearings go bad at once? Checked belt it's not to tight, I am running a 4lb lower and it does seem to look like it is vibrating alittle when you shine a light on it so I pulled it off and couldn't find anything wrong with it. Noticed the rubber on the balancer looked fine it's not pushing out so im at a stop until I can think of something else to check? I also had to change the snout at Mustang Week this year , the bearings in it went bad as well ..... and here's the funny part car only has 10,000 on it. I know something is going on just can pin point it. Anyone had this issue before? Thanks