Lookin for rust in all the right places found the driver side jack support has rusted through only on the bottom do I need to replace the whole thing or can I just patch bottom aera and prime .Evry thing looks pretty solid after poking around with screw driver.Any Ideas.

The OE post suports had "drain" holes in the top & bottom. Naturely stuff goes in the top and rusts out the bottom.
I cut off the support on a straight line flush with the bottom of the post to chk out if the rot was impacting the long. It wasnt so Im planning to just get cut a replacement support plate in .5, replace and weld up the stupid drain hole at the top!

Sounds like what I might do thanks

The drain hole at the top was for drainage if the car was flipped over. I think I would leave it there.

Post a pic of it.