For the Cummins B's and C's there has been what I consider, a high failure rate of the of idler pulley

IDLER Pulley Issues---Cummins 6BT / 6BTA 5.9 For the Cummins B's and C's there has been what I consider, a high failure rate of the of idler pulley on the front of these engines.. What’s actually failing is the center 10mm bolt (hex head cap screw) as it is shearing off at the bracket.. This goes back at least 6 yrs and the factory has made a couple of changes, but from my view has totally failed to fix this reoccurring problem.. By inspecting the attached pictures, you’ll see the difference between the new parts vs the old parts.. I think the intent of the engineer that was assigned to this upgrade was to increase the surface area of the spacer where it is tight up against the bracket, additional support and lessening the leverage.. All he did was change the diameter just behind the bearing and DID NOT change the footprint of the spacer where it needed to be enlarged.. This is another example of true “couch engineering”..I tried to give some input to the factory about 10 years ago as to what needed to be done and the factory guy that was at my shop agreed. He even said “why such a cheesy bolt size, couldn’t they just use a larger bolt”. That is a very accurate quote as far as the content of what he said.. So where are we at this point…. I decided 10+ years ago to start doing the pictured upgrade….Replacing the 10mm bolt with a Grade 8 7/16 x 2 ¾” bolt and nut.. This requires drilling the spacer (new or old style) to 29/64” and drilling the engine ...