NineMeister

Maybe it's the weather, but for some strange reason there seems to be a never ending stream of 993's appearing at the 9m workshop with "untraceable" water leaks. Almost without exception we are finding that the root cause of the leaks is corrosion around the front and rear window apertures, probably as a direct result of incompetant windscreen fitting, so I've started this thread as a warning to show you all what could be lurking under your screen rubbers when you spot a little bit of bubbling under the paint, just like this .......

NineMeister

.... and when you remove the glass, this is what you find. This is the rear screen aperture of the silver 993 and the front aperture of the blue one.

air klwd

Did Southern California cars ( basically born and breed here) just go up in value????? LOL....

NineMeister

We start the repair by sealing off the inside of the car, then stripping all the paint from the entire screen aperture. Heavy corrosion has to be cut out and repaired with new metal, in particularly bad cases we will probably use repair sections cut from an accident damaged car as it is quicker than hand making pieces to suit.

matt777

I'm about to have my windscreen replaced. What is the actual root cause? Are there drain holes that are being plugged with sealant? That would explain corrosion in the lower areas but not up the sides. Perhaps the paint has been scored when they cut out the old windscreen. Even most 40 year old American muscle cars don't rust that bad (at least the ones that are still around today)

sonny1

This is not neccesary a case of bad windshield fitting, I have seen this in original cars without prior work done on them, I have noticed that water collects under the seal lip,and it does not have a way to evacuate from there and uppon time this happens, my suggestion is to blow dry after a wash all this stuborn spots.cheers.

NineMeister

Once all traces of heavy corrosion has been removed with a mini-grinding pad or flap disc, any fine areas of pitting are detail prepared with a detail glass bead blaster.

The fresh screen aperture is then etch primed, primed & painted. In the case of the yellow 993RS pictured here, we have stopped the paint on the seal edge so that we don't have to carry the paint up through the roof, however in some rare cases the corrosion is so bad at the top of the screen there is no option but to paint the roof as well. If (as more often the case) we end up painting the front and rear apertures at the same time, we will definitely paint the roof as well as it saves time with the overall job.

As a guide, to remove a glass, repair & paint the front aperture then fit a brand new factory glass & rubber will cost around £1500 including VAT. Sure, it's expensive to do it right, but this still costs less than a new Motronic ecu and alarm module which are the first items to fail when they get submerged in water!

Wilder

+1. This was the unfortunate case on my old 35k mi C4S (rear glass) as shown to me by the PO whom I've befriended. The car didn't have any work to the rear glass or surrounding area (to my knowledge).

I also had the windshield leak on my cab after the PO replaced the windshield. I was lucky in that the problem on my car was dealt with quickly and therefore it was at no cost. Here is the thread I posted on: https://rennlist.com/forums/993-foru...-now-what.html

ZombiePorsche44

God I really hope so!!!!!!!!

H.H.Chinn

This can happen to all vintage 911s not only to the 993. When I repainted my 82SC, we addressed some very minor surface rust that would most certainly have worsen over time.

JM993

E30 M3s too.

Whenever I wash my car, I always lift the seal edges at the bottom corners of the front and rear glass and dry the area underneath.

cheers,
Joe

vincer77

Boy that is ugly! Is it possible to lift the rubber seal to look for any problems? Or is windscreen removal the only way to see the rust?

ironimages

9m, thanks for all the info and pictures, informative as always.

Ed Burdell

I can barely see the paint bubble noted in the first picture of the thread - it is that light colored area above and to the right of the VIN# plate, right along the edge of the rubber window seal?

AOW162435

Those pics are numbing. I have made a habit, after each washing, of inserting small wooden shims under the four corners in order to let the water drain.


Andreas