Anthony, your pictures have uploaded okay, I have inserted one for you just to check.
If you edit your post, click on the upload picture button, select the gallery option and you should see your other 3 pictures, choose the one you want then click on the “standard” link – that’s the bit that actually puts the picture in your post.
The rubber “brake” is the only thing that should give any resisitance to the centreboard moving up and down, and you can adjust that with the centreboard in situ on the water.
It sounds as though you may have inherited a boat with the bolt overtightened. You can check that by removing the brake (the rubber bit on the top edge) and just seeing if the centreboard slides easliy into the case.
Also looks like you do not have an epoxy resin plug in the wood that the bolt goes through.
All the Porters boards that we have had come with one of these. I dont know how tricky it would be to make and fit one. But anyway I think some kind of bearing for the bolt is desirable. If it is just on wood then that will wear and you will get movement.
The more recent centreboard bolts would have big metal and rubber washers, otherwise it will leak. It wants to be tightened so that the washers are just snug on the outside of the case. So I would guess yours wants these as well.
Let me know if you still have trouble loading the pictures.