Got rust bubbling near your sunroof? Look in here

[glucklich21]

I did and here's what I found when I was replacing my door seals

I first poked with a screw driver underneath and caused these:



Here's what it looks like under there:



And after some grinding and more poking:





So yeah.......

Going to use this thread to document what I'm doing to fix it since I'm trying to sell this e30 and be as transparent about it as possible. Also to help others as I doubt I'm the only one with these "bubbles".

[glucklich21]

My local Fastenal happens to carry some 3M Ultrapro Seam Sealer. It's primary usage? Water proofing automotive panel seams. :)

Given it's $30 for a little tube, but I need it for this repair to be successful.

Also repair #1 in the sunroof rain channel didn't take well (see pic #1) so I'll be fixing that as well now that I'll have some real sealant.

[glucklich21]

Garey on E30tech questioned what I was doing to stop the bare metal from rusting, so here's how the metal is going to be prepped.

• Bare Metal
• Rust inhibitor coating
• Etching Primer
• Zinc Coating
• Paint

Here's what I did today. I was only able to work on the holes for about an hour and a half before I had to go to work. I work 12hrs a day and slept a little bit too much today.



I started off with a copper plate and some magnets under the roof to give me something to make contact with and something to fill against.






I added some tape so hot flying slag from messing up the rest of the paint. This was the first pass after the dremel. This took about 10 mins pausing in between to let it cool.





Second pass:





Grinded:




Moved onto the holes below the first ones I worked on:







And then my dremel died after 5 years of doing things it was never meant for. :/



So I made a quick run to Home Depot and bought a new one before work to continue tomorrow.





I say not too bad for my first time trying this. There are a few pits in the areas where I added, but not any that are holes so I'm happy.

I will say that the pinholes are the hardest as they're so tiny and thin it's difficult to fill them without burning through. I ended up drilling the pinholes a little bigger for easier filling and so the metal is the thickness it is suppose to be.

More tomorrow.

[glucklich21]

Almost done welding, one more hole left on the right outside of the pic.

[glucklich21]

Finished up the rest of holes today.




Smeared some bondo on it so it will be cured for tomorrow to start sanding. And I'm aware that this may be too much, but I rather start with too much and sand it all away then have to reapply a few times to fix some divots. Right now its the same thickness as the paint around it.

[glucklich21]

Here's after the first sanding with the bar sander.



You can see here how low my welds are.




First primering.








Other than that I didn't get much done on the roof. I had a big to do list today on the rest of the E30 to get it ready for Austin. Said things included:

new heater core
checked thermostat position
replaced alternator bushings
dyed the rear M3 seats
changed rear brake pads
soldered new E36 switch bases (old ones had crumbled)
install new window felts

So I was busy. :)

[george graves]

Wow - hats off to you. That doesn't look like an easy fix!

[nickanicus]

Sorry to bump an old thread. I have to do pretty much the exact same fix on my car. Is this considered a good way to fix the problem permanantly?

[jeffnhiscars]

Sorry to bump an old thread. I have to do pretty much the exact same fix on my car. Is this considered a good way to fix the problem permanantly?

I would say definitely, maybe, sorta

The holes he fixed should not be a problem again, BUT IMO there is no way a car gets those without having other spots just waiting to corrode their way through.

[glucklich21]

Sorry to bump an old thread. I have to do pretty much the exact same fix on my car. Is this considered a good way to fix the problem permanantly?

I would say definitely, maybe, sorta

The holes he fixed should not be a problem again, BUT IMO there is no way a car gets those without having other spots just waiting to corrode their way through.

No welding in fresh sheet metal instead of just filling it with welds would be better.

The cause of this is the seam sealant failing near the sunroof drains and letting in a little bit of water in each time and slowly eating it out from within. So fixing the sealant issue should take care of future problems in theory at least.

[jeffnhiscars]

It's not a typical rust issue but you both know your car(s) better than I do, so sure, it could be isolated. I've just seen so many rust "repairs" that just hide the problem.

You did a good job

[VinniE30]

The cause of this is the seam sealant failing near the sunroof drains and letting in a little bit of water in each time and slowly eating it out from within. So fixing the sealant issue should take care of future problems in theory at least.

Could you show where this pic was taken from farther away?
Is that between the drivers side window and the windshield? Or in the back?

[glucklich21]

It's not a typical rust issue but you both know your car(s) better than I do, so sure, it could be isolated. I've just seen so many rust "repairs" that just hide the problem.

You did a good job

I've seen the bubbles on every late model I've come across that has lived a good chunk of its life outside.

Could you show where this pic was taken from farther away?
Is that between the drivers side window and the windshield? Or in the back?

On driver's side between the sunroof and windshield. If you drop your overhead panel and pull the headliner back you'll see it.