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Windscreen rust


21 Dec 2012
Hi guys, first post !!! :wink:

I've been cramming as much info as I can on 964s before I go out looking for one.

I've got a good idea of the potential rust areas etc but would like a little bit more detail. Is the root cause of the rusting found at the corners/base of the windscreen properly understood? I can't see how this is an area where water can easily collect or paint damage occurs allowing the element to penetrate. Anybody got any details or theories?

Many thanks

I dont know the physics behind it but believe me they do rust around the windscreen - from the side A pillars and along the top of the scuttle.

Some say movement of the windscreen can bare the metal aloowing rust to form when water gets in. I've seen plenty including cars priced at £20k. Picking at the rubber will reveal more.

Then you have the problem of the water running down the scuttle underneath the rubber 'join' and onto the wing underneath where it bolts and the bonnet covers it. If neglected the tops of the front wings rot.

Then you have the rear wheel arches - no plastic liners (improvement for 993) and leaves body prone to attack. Behind the rear lights sections (no vents/drainage or rubbers) is also an area. As is under the rear bumper.

Then the side skirts. Any rust bubbles forming above the rubber line is likley to lead to big rust holes underneath.

Rear edges of heel arches can lead to surface rust from gravel rash if neglected.

993 suffers windscreen rot to similar degree but remember 964 are now 20+ yrs old.

For me I'd concentrate on the windscreen and side skirt areas first. Sometimes you will get lucky it may have already been done or the car has hardly been used in the wet (as was my 993 and through lack of use I sold it but regret it most days :pc:

Other than that they are not bad cars :thumb:
Thank you for your detailed response. I wasn't aware or the area behind the rear lights. I've searched through the forum and seen many have had the windscreen rust addressed but few comment on the actual repair process. I assume the screen is removed beforehand but how are the holes left by the corrosion repaired? I can imagine its quite had welding an A pillar. I'm not looking to tackle the problem myself, just understand the process.


When I first saw my 964 there was rot above the rear bumper near tail lights and also behind the sharkfins on both sides. I guess water collects there over time. You can get someone reputable to cut out the rot and weld these areas with no difficulties. I managed to get the dealer I bought mine from to include this work in the price advertised as well and I am very happy with the results.

Mine also has a small amount of rust forming around the skuttle on both sides of the screen, a little under one of the headlights and strangely some inside one of the roof sills (not sure what it's called). I clean my car regularly because it is driven daily and I hate it getting filthy but each time I clean it, I check for any changes to these areas.

As my 964 lives outside and is driven whatever the weather I am willing to put up with a little rust until the spring when I plan to enquire and investigate (and I will hopefully move house and have a garage big enough to keep the car in!).

I would say it is probably unusual to find one without rust now - unless all has been treated in which case you will pay more. Depends on how often you plan on driving it and if it is going to be exposed to the elements frequently.

However much I want to protect my 964 there is no way it will be a garage queen - it is so much fun and makes every drive an event!

Enjoy the hunt! 8)
Eeeesh scary pictures!

I'm budgeting 20k for a manual coupe but only seriously looking at vehicles from specialist dealers or recommendations that have a lot of this kind of work done. I'll want the undertrays removed as part of the viewing (not a problem as most specialists have lifts) but is it too cheeky to ask for the shark fin sills to be popped off also ?

also.... the area behind the fin, I assume the rust starts on the inner side and works its way through to the painted finish. Can these inner areas not be better protect by the the application of Tetra Schutz or something similar?
Ok, getting proper concerned now!
Are we saying that even if you lift the seal a little, peer all round and see nothing, it doesn't mean it's not there?
Is it more the case that it *WILL* be there, and its just a mater of how far its progressed and visibility suggests alot?
robt964 said:
Ok, getting proper concerned now!
Are we saying that even if you lift the seal a little, peer all round and see nothing, it doesn't mean it's not there?
Is it more the case that it *WILL* be there, and its just a mater of how far its progressed and visibility suggests alot?

There may be 'something' there given the design but I wouldn't take it on until you see physical symptons and you cant live with it. Then when you do get it done get it done properly by someone who knows what they are doing.

Others have been lucky with just surface rust noticed when they have had a screen change so my view is there are many variables as to how and when this corrosion occurs.

One option is to buy a car to restore and set aside £5k for a glass out full respray and all rubbers replaced.

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