Dear Vangonauts

I just came back from a 1,100 round trip and everything went fine with one exception.  I was dealing with some stiff cross-winds on the way back and the van seemed to sway much more than normal.  On a post-trip inspection I found the lower bolt had fallen out of the front right shock.  Would anyone know what size bolt that takes and what it should be torqued to?

Thanks in advance
Dave B
Boise