Seam rust can be terrible. I'm almost done replacing 10 panels on a van that didn't look very rusty....
That van pictured though has very minor seam rust. If it were me Id remove the seam sealer on the affected seams with a dental pick and clean them out with some metal prep. A thin layer of etch primer sprayed into the seam and then a fresh application of seam sealer ( them painted with a brush to match the body color) will stop it. Annually applications of fluid film to the entire underside and behind interior panels will help alot as well. 

-craig

On Jul 2, 2013, at 10:21 AM, Jason Ellsmere <j@BEAUS.CA> wrote:

> Hey Guys
> 
> Looking at a van that is very clean with the exception of these 2 bits of rust on the seams.  I have read that seam rust on the outside is the tip of the iceberg so I'm wondering how big of a iceberg these would be.  Are they significant enough to be concerned?
> 
> Didn't know if I could send pictures to the email group so I threw the pictures up on my unused blog.
> 
> http://www.laidbackdad.com/vanagon/
> 
> Any feed back is much appreciated.
> 
> Thanks
> Jason
> Toronto