If you look at the design closely you will see that the U-joint is
installed greater that than 50% which puts ALL of the load in
the yoke.. all the bolts do is to keep the caps snug and dont really
take any load...some if the fancy girdles tend to bind against the
yoke specially if the pinion angle is to much.. this causes the bolts
to stress and break.. just make sure the yoke hasnt spread.. is
it has.. get a new yoke