How to fix leak?

[Kbratko]

Looks like I have water leaking through a bolt that holds the starboard side top deck rail, where pad attaches to. 2005 320da.
I have access to the bolt but don’t know what to do next. How and what do I use to seal it? From the inside or outside?
Thanks

 

[Lazy Daze]

Remove all three stanchion bolts. Ideally you'll be able to lift the stanchion base a bit. If not, you may have to remove neighboring stanchions, or more, for the best repair (and obviously reseal those). Clean things out. Slip some butyl rubber tape in between the base and the deck. Stuff a little in the hole and around the bolt, near the top, under the head. Re-tighten everything. A step down from this would be to use somethign like LifeCaulk, or similar (NOT 5200), with only removing the 3 bolts.