A reminder to check your 996 for rust

Hello fellow 996ers. Just wanted to stop by to share my recent experience with rust, in the hope it helps someone else. I‘ve been in the rear corners making some suspension changes and decided to whip the arch liners off of my 2001 996.1 to see what state we’re in. Glad I did, because I spotted some rust along the weld seam, and things were getting particularly crusty at the lower corner, where the cross-member brace attaches to the body. I actually had to strip back quite a bit of sealant to get to clean metal, but in both locations it’s all still pretty solid steel, no major structural damage. Should be able to be saved with a bit of a clean up and a decent coating of paint etc. Needless to say, this was all caused by 25 years of muck building up under the liner that no one cleaned. So if you haven’t done so yet, might be worth checking this for yourself in case you need to address something now that might become a much bigger problem later.

Taking the liners off is a job I need to do this winter so a timely reminder

Porsche underseal has ever been great stuff, however if damaged by cuts, unfortunately it is also great at holding damp crud against the metalwork which begins corrosion which can work it`s way along behind the underseal.... Which Wenniepy`s second image seems to show, given it looks like the heavy underseal has been cut away to reveal that which lies underneath...?

Second picture was before I started cutting that corner patch, believe it or not. Hard to say quite what caused the underseal to come away, but I guess as soon as the corrosion sets in, any surface adhesion will go out the window. I’m hoping the inside of the sill isn’t the same, as that will be a bit trickier to deal with!

This is after just a minute or two with 320 grit to gently see what’s what. I’m quite hopeful it’s salvageable, but I need to get proper access and cut some more away. Need to remove the cross member and peel back the under tray ideally. A job for tomorrow.

On mine the NS was really good but drivers side had a hole in it that required welding a small patch in. Definitely a job that needs doing every few years. It's very hard to access that cross member bolt if you've got a lift/jack pad on the jacking point , you can loosen it but getting it out is tricky.

Yeah, I have to replace my subframe side carrier this week (self inflicted, don’t ask) so I’m going to have jacks, stands and detached wheels in all sorts of funky places I imagine!

Thanks for the heads up Wennypies, I suspect a wire brush will get into the areas where the 320g skips over...

Thanks for that - one of the first jobs I'll be doing when I get my 'new to me' 996.

had the undertrays off mine recently and a full under body clean & waxoyl ahead of winter. There are a few areas where I am glad I did it sooner rather than later

They can get really bad I’m in that area on mine at the moment. Tons of crap collects behind the arch liner Ive got the plastic corner spats off (had to butcher it and drill off the screw heads) and the cross brace bar to have a good poke around, mine needs a couple of small fiddly weld repairs drivers side. UK car Stuck the scope down the box sections and all good beautiful grey coating inside thankfully.

More or less the same as mine Bert on the OS , NS was fine It's a very awkward shape to weld in so I got someone else to do mine. Inside the actual sill was perfect.

Sadly becoming increasingly common, I think. Does this mean we can start calling them ‘classic’ cars now? Has anyone had a go at sorting the jack points yet? Is it as simple as cleaning and coating the visible face? Or just something need to be done up inside the centre hole?

They too are a rot trap so best to really blast all the crap out and try to get as much bare metal exposed as possible then a good epoxy primer and paint followed by underseal of your choice. If they're rotten (like one I went to look at on a 400mile round trip) it's a big job to weld in new ones , interior has to come out. They literally crumbled in my hand and fell into a pile of rust on the owners driveway , I walked. That entire rear corner section is a good place to start when viewing a car but those plastic covers need to be off and that means lots of other things too like the arch liners.

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Sure enough, NS was almost perfect on mine too. I wonder what causes the difference, if there is a significant one? Could help with preventing it from returning.

Someone on here and I can't recall who it was suggested it was because the NS gets all the puddles which rinses all the crap out but the OS doesn't due to camber of the roads. Sounds plausible.

If the theory’s correct LHD cars will go the other side ? Unless they’re somewhere warm & dry