Roof rust question

[poohbah]

Folks, have just spotted two little rust bubbles (small - less than 5mm across) on the rear-facing lip of the roof panel on my 156 - on the vertical edge facing towards the rear windscreen.

They don't appear to extend to  the skyward facing joint that runs parallel to the top of the rear screen.

My question  - is this an area particularly prone to rust on the 156, and is it likely that it actually originates from the actual join? In which case, is it likely that I will need to pull out the seal that sits between the main windscreen seal and the roof panel?

Alternatively, if I just scrape and fix the visible rust, do you think I risk it spreading along the edge where it can't be seen?

I'm quite prepared to have a crack at minor surface rust repairs, but anything more complicated and I would want to leave to a professional.

[ANG156]

Hi,

Whats happened is that your rear screen was probably removed at some point. Since the rear screen is bonded, you need to use a blade to cut it first then pull out the window. When it was removed the paint was probably scratched down to the metal and the installer did not apply a coating other than the new sealant. Now water has got in and is causing the rust. I've removed my rear screen and re-installed it with no issues in 4 years. I'd say it was a poor installation not caused by the factory but by a third party at some point.