Seam glue splits

[SurfT25]

I keep my bus undercover, (bad leakage on hi top, need to replace gutters) but have recently noticed that the glue/sealant down my panel seamsare splitting from top to bottom and I have now got rusty watermark on most of them. No rust rash or blisters, just rusty watermarks.
Has anybody had this before, and whats the best way to cure, resolve this issue?
TIA Peter

[Stesaw]

You'll have to dig out the sealant and treat rust and reseal.
Once they crack they let water in and they will rust.

[silverbullet]

Leaky gutters mean water is already doing its thing with the steel and oxygen, from the inside out. I would think that splitting seam sealant and rusty streaks are bad news.

[SurfT25]

Thank you both.
I have been trying to think of the best approach to this problem, yes remove the sealant, but which is the best method. Disc plate, wire wheel, shotblast or some other method.
I don't have a garage so will have to work outside, could this cause more damage through exposure?
Have bought a large market stall frame to try and get some protection.
Also what's the best rust treatment and sealant to use.
Many questions and answers I feel like Marvels Dr Strange trying to find best solution
Any suggestions much appreciated

[silverbullet]

Fix the roof and gutters first or its a waste of time. You need to be under cover because there will alway be more to do than you hope.

[SurfT25]

Thank you Silverbullet,
Will do, I am looking into constructing a car port on front of my house. Something open that I can screen off for protection while working on bus.

[silverbullet]

Its the harsh reality of working on these old vans. Campers have sweaty bodies inside them for overnight, which turns to mildly corrosive condensation, so they rot from the inside out.
Then adhesives retaining hitops fail through old age and "suddenly" there is water and rust everywhere.
There's no way to sugar coat it. Sorry.