Vertical movement at left rear pylon.

Hello all. I'm slowly fixing up and enjoying my new to me 1980 Hobie 16. Sailing it is a blast. It is old but in decent shape.

Today I discovered about 3 millimeters of vertical movement at the left side rear pylon. The pylon is sliding vertically in the casting. I tried tightening the bolt but it didn't really help and I didn't want to over tighten. All the other pylons seem fine.

I've read about putting in shims or using epoxy (I don't want to use epoxy as I want it to come apart again). From what I've read these seem to be solutions more for lateral movement rather than vertical.

Does anyone have an further suggestions for fixing vertical play at a pylon? Thanks in advance!

Make sure the movement is really not the pylon moving 3mm out of the hull.
Next, check to see if the holes in the pylon have gone oblong.
If they have, I would go to the next larger stainless steel bolt and drill out the
corner casting and the pylon to fit the new size.
Note: those bolts are only suppose to be snug. Not cranked down on to get snug
around the pylon. The corner casting are, well, castings. And cast aluminum does
not compress. It will only crack and split apart.
Good luck.
Greg 1984 H16

Thanks for your help. It's definitely the pylon moving in the casting. In the end I will probably do what you said and use a bigger bolt. I'm a bit chicken of drilling so first I may try putting a couple millimeters of shims on top of the pylons to "eat up the play". It won't be until next season at the earliest that I solve this though.
Thanks again.