Cotter pin substitute?

[MillWeld]

My Al-Ko axle has a curved pin hole to allow for a zerk fitting in the end of the spindle for lubrication. I can't see any other reason for a curved hole. The dust cap originally has a removeable rubber cover for easy access to the zerk but I replaced it with a steel cap because the rubber was cracked.
Bob

 

[Diamondpilot]

My Al-Ko axle has a curved pin hole to allow for a zerk fitting in the end of the spindle for lubrication. I can't see any other reason for a curved hole. The dust cap originally has a removeable rubber cover for easy access to the zerk but I replaced it with a steel cap because the rubber was cracked.
Bob

You can get the rubber replacements for about $.75 each at any RV or marine dealer.

Chris