Do I Need to Have a Castle Nut or Cotter Pin to Keep Spindle Nut From Backing Off

Updated 04/28/2025 | Published 09/06/2022

Question:

i replaced my bearings on my 1993 bass tracker boat trailer, and i found that there are no castle nuts or cotter pins anywhere. the only thing that i found was a thin metal washer the same diameter of the bearing and the nut. is this correct or do i have to worry about the nut coming off

asked by: GARY

Expert Reply:

If you only have the nut and a washer but no cotter pin or retaining type washer on the end then that isn't correct and you want to get a piece to help prevent that nut from backing off. If you have a setup like the Spindle Nut Kit for EZ Lube Axles # RG05-100 with the weird looking washer on the outside then that is okay because the weird washer is designed to help keep the nut in place.

Let me know if you're needing something to secure it and I can help you with the correct part if you can let me know what diameter spindle you have.

expert reply by: Jon G