We have a 70 ton link belt with a tensioner pulley that operates the fan. The bolt continues to shear off in this pulley. I purchased a new pulley (3500$) and what do you know still shearing the bolt. Any one have any ideas???
Too much tension on belt? Are all the accessories run by this belt aligned properly? Anything wobbling or have excessive runout? Another part locking up causing excess stress on things and the bolt is the weakest link? Is the bolt being run too tight after adjusting tension? Lots of things it could be....if there's something unhappy in there I would think you will be able to see it while the machine is running. Any other issues lately bedsides this tensioner problem?
60 series detroit? Cummins? Cat? Link belt has used all three, but this isn't a link belt issue, just a engine issue. I would tend to think some bracket is loose or has worn the housing where it sits on the engine, and like junkyard says its mis aligned itself.