Crestliner Wipers

[MDT]

For those of you with Crestliners that have a windshield wiper(s), how do you keep the sleeve that fits over the wiper motor shaft from slipping? It is fixed by one setscrew, which will hold for about two swipes and then slips. I have contemplated lock-tight, epoxy, and a roll pin. Any suggestions?
Thanks,
MDT