The best way to go is first remove the parts and then take them to a Trailer repair shop and replace the parts with new that are the same. Sometimes auto break parts are not the same.
Bottom line is drum breaks are junk for boat trailers. Disks are much better and Stainless Steel parts are the way to go. I read about your use you need to make these decisions.
FellowShip
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Just for the Grins
Official Antique Classic SeaCraft Owner