How do I stop rust progression on seams?

[MKMike]

Investigated some water leaks in my recently acquired midnight blue 2001 SSEI and discovered that one leak was coming from the weld above the sunroof RR drain tube.
Turns out the water enters through the long windshield to rear window rain channel.
After removing the rubber tube from the channel, I can see some small rust spots on the seam and inside there is rust along the same seam.
I can use 3m Ultrapro urethane seam sealer to keep the water out, but shouldn't something be applied first to halt the progression of rust?
I know there is Rust Bullet Clear Liquid Metal Blast Rust Treatment and Rust Remover but it would be difficult to get it where it needs to go inside the rain channel, not to mention it may be tough to keep it from accidentally going elsewhere, too.
Looking for good ideas before the cold blast hits the northeast states.

[96 SSEi]

get rid of as much surface rust with sand paper, then treat with rust preventer with q tip. do not leave exposed unpainted surfaces exposed overnight. once rust is treated, seal the leak

[00Beast]

Yeah, you need some kind of POR or rust converter on the rust first, let cure, then seal with seam-sealer.

[MKMike]

Yeah, you need some kind of POR or rust converter on the rust first, let cure, then seal with seam-sealer.

I appreciate the replies.

What is POR?
What rust converters are best?

get rid of as much surface rust with sand paper, then treat with rust preventer with q tip. do not leave exposed unpainted surfaces exposed overnight. once rust is treated, seal the leak

That's good to know.
I've never done any type of sheet metal repairs, so the more info, the better.
There is really only rust in the seam, so I don't believe I can actually sand it.

The biggest part of the water leaks may be the lower parts of the front sunroof tubes--I hope--but I want to seal all leaks and prevent further rusting as much as possible.
Only had time to remove the seats, the wet in the rr corner headliner and the "so wet that the carpet backing couldn't even absorb it all on the rr" rear carpet so far.
With the aid of forum members and, past posts about water leaks, I hope to seal this sponge up!
Once that is accomplished, I will replace the headliner and, after I locate some Microban, get the carpets in clean, stink-free condition.

[96 SSEi]

What rust converters are best?

products with a high content of phosphorous works best. sadly, not many list ingredients

[Archon]

I talked to the guys at a local body shop regarding what they use. They suggested using "Chassis Saver".
http://www.magnetpaints.com/underbody.asp
It isn't necessary to remove all the rust, just the loose stuff. It works better leaving some rust behind. It is not inexpensive, so I bought a half pint at Amazon. It hasn't been on real long, but so far it seems to be doing the job.
http://www.amazon.com/Chassis-Saver-Ant ... ssis+saver
Try to seal the can well, after using. However, from what I've read, it doesn't last real long once the can has been opened.

[MKMike]

What rust converters are best?

products with a high content of phosphorous works best. sadly, not many list ingredients

Seems like a problem with so many things today, unfortunately.
Thanks for the info, though.
Maybe I can scan some MSDS and see if concentrations of phosphorus are listed.

I talked to the guys at a local body shop regarding what they use. They suggested using "Chassis Saver".
http://www.magnetpaints.com/underbody.asp
It isn't necessary to remove all the rust, just the loose stuff. It works better leaving some rust behind. It is not inexpensive, so I bought a half pint at Amazon. It hasn't been on real long, but so far it seems to be doing the job.
http://www.amazon.com/Chassis-Saver-Ant ... ssis+saver
Try to seal the can well, after using. However, from what I've read, it doesn't last real long once the can has been opened.

It would seem likely that a body shop would have a good idea as to what's effective (though I always wonder whether or not a business prefers price over long-term effectiveness).
I'm hoping to not have to re-address the issue, so maybe a short shelf life won't matter.
With a deep hatred of shopping, online ordering is always a favored option.
Thanks for the links.

In this particular spot, there is little accessible rust and fortunately, it doesn't seem to have been going on for a very long time.
The cause, I suspect, is that organic matter (pine needles, leaf bits, etc.) get trapped behind the flexible drainage tube and then hold the moisture.
Perhaps it was because the previous owner was diligent enough about washes and waxes that it took 14 years to become an issue.

[jdecker]

I've had good look with the stuff from Eastwood. Never tried POR but I did notice it on sale on Eastwood site. I've been trying to slow a rotting Ford Expedition for awhile now, it's no fun.

[MKMike]

I guess this would be a good first step , especially for rather inaccessible spots http://www.amazon.com/POR-15-40201-Meta ... op?ie=UTF8
Living in an area where the roads are salted, this is probably the size I need , too.