I agree that steel rivets would be better than the bolts.  I am not certain of the difficulty in squeezing them, but they would provide a “press fit” where the bolts would not.  The strength would be similar in shear which is where most of the forces would be.  They would also be a lighter, important in a rotating mass.   The idea of putting something like “Proseal” in before assembly makes sense as well.  The combination should ensure that shear forces would never move it.  In the current situation it must be moving else the rivets could not loosen???

 

Bill B

Sorry guys my system glitched. I sent the e-mail too soon. An adjustable reamer is available at most machining supply places. The bolts may be slightly different, but you can buy a few extra to get some of the same size. Get some jet nuts or be sure you locktite or safety wire the nuts too.

Bill Jepson