I've seen a similar problem before. The issue is that air can go through drain tubes, but it may not actually get the clogging agent out. 

In my case it is the seeds of the Tulip Poplar. They really are a pain. You need to get something physical down those drain tubes to actually clean out the crap. Then add a screen at the top to filter out the seeds, or whatever. 

On Sep 2, 2013, at 9:25 AM, Jim Akiba <syncrolist@BOSTIG.COM> wrote:

> Hey All,
> 
> So I've cleared out the 4 drains repeatedly with air, but the sunroof
> syncro still likes to accumulate oh about 2-3 GALLONS of water and
> then conveniently dump it on me when I brake from the sunroof opening
> (it's actually hilarious, good thing I know about it)
> 
>  The seal has been replaced, but no seal is actually perfectly
> sealed, so it still needs to be able to drain but isn't. Does anyone
> know what might be going on or have/dealt with this issue before?
> 
> Thanks!
> 
> Jim Akiba