I'm not sure why castle nuts were used as the bolts didn't have corresponding holes for split pins,at least the ones on mine weren't and as far as I know there were the originals.
Are the new nuts longer than the threads on the bolts?
Ideally there should be some exposed thread once the nuts are tightened down fully.
If not i'd be tempted to get either slightly longer bolts or shorter nuts,nylocs would be even better.
