Centerboard wobbling on CB 57 Lianda

Since we recoated the centreboard after cleaning the corrosion on the aluminium, which was blocking it inside, we have a constant fore and aft movement when the centreboard is lowered . Is it a way to stop this? 
What you see on the pictures was before we did antifouling on the centreboard.

Sliding the centreboard back inside

Re coated centreboard

We could only slide the disc on the starboard side. Not on the port side

Dear Marc,

had the same problem on 47/069 Vanessa, which was fixed after changing the two Delrin discs. Aren't you able to get the second disc out, or is there only one (which could be the reason of the problem)?

Did you notice any corrosion on the shaft where the lifting rope goes through?

matteo (47/069 Vanessa)

Old delrin disc