Hello and help with my 996 project

Hey everyone, a new UK based member checking in. I collected my new (to me) 2002 C4S over the weekend. Its fulfilled a long term dream, ever since reading about these cars dominating the Evo group tests back in the early 00's. My car is a Seal grey with metropole blue specimen with 75k miles on the clock and a few problems to work on, keeping me busy over the winter. The car's only done 20k miles in the last 10 years so there are a few things that need attention. The first is the slightly scary brakes with a spongy pedal and lack of retardation. Its going in for a fluid change shortly. Second, I suspect the clutch is on the way out. I can't do an aggresive launch, all that happens is brisk acceleration and whiffy clutch smells in the cabin. There's no slipping while normal driving, is there anything else I should look out for to confirm its the clutch? And what other jobs should I tackle while replacing it? IMS, RMS? Potentially a light weight flywheel? The AC also doesn't blow cold. The condensors look OK, though I'll check them properly soon. Time to hunt for other wet spots when I get the car up in the air. Those are the biggest things, after that there's some tired trim that needs replacing and 4 wheels that need refurbishing, nothing serious. One thing that I need the collective's help with is dealing with some highway speed wind noise. Its only on the drivers side and I thing its caused by the mirror housing. Comparing left to right sides, the top of the housing sticks out, see the attached picture. I think this is the cause of the wind noise as everything else seems the same. Is this normal? If not, how do I fix it? I think I need to take the mirrors off anyway to re-black the plastic so its a perfect time to sort this out. See how the top of the black plastic sticks out on the left image compared to the right. Aside from that, it pulls hard, doesn't seem to creak or rattle over bumps and sounds amazing, if a tad quiet. I'm very pleased and can't wait to get stuck into turning this beauty back into the shining star it should be!

Definitely do the IMSB while the transmission is out. At that age/mileage I'd say do the engine and transmission mounts as well. I believe AOS is easier with the transmission out too? Someone else can verify. I personally wouldn't put a lightweight flywheel on anything but race engines or track toys. The dual mass flywheel is integral to the balance and smoothness of the engine. Congratulations on your new toy!

Welcome to the club. Mine is an 02 base, but I read your post and went out to look at my mirrors and mine look identical to your pictures. The passenger side one is nice and flush with the frame while the driver's side flares out at the top just like yours. And this is interesting because yours is a right hand drive and mine is left. No wind noise here. From your description, you definitely 100% need a new clutch and flywheel. I would go with the dual mass as wdb said and not the lightweight. And while that is out, you should put in one of the IMS Bearings that either lasts forever, like the LN Engineering Solution, or if you are already at your budget max, choose an option that is at least warranted. You should be aware that the stock coolant filler cap needs to be replaced, and if the expansion tank is original, that should be updated as well. You should replace ALL fluids. As for the brakes, if replacing the fluids doesn't fix the issue, then you have some more work to do. When I took possession of mine, the AC also didn't work, but it was because the lines under the car were crushed, so check those. wdb suggest engine mounts and at that age, it will be needed at some point, although that is an easy DIY that you can do with the car resting on the ground. I mean its easy if you have a 2-meter breeaker bar. Get your eye even with the bottom of the rear bumper and look at the catalytic converters. They should both be hanging such that they are parallel to the bottom of the bumper. If one side is lower, then you have a sagging motor mount for sure. If they are both sagging the same amount, then we need another way to tell if they are shot.

Consider the possibility that your wind noise is actually harmonics from the tires. I have a whistling noise from my tires that I was sure was my mirrors, until I went over some fresh pavement and the noise disappeared.

Hi-- I am also UK based, lurking in Devon and am now in my third year of a 99 C4 cabriolet which I and my wife adore. I have had some of your issues but then my mileage is lower. I changed the brake discs (rotors) and pads (EBC Yellow stuff)and flushed out the brake fluid with new. The PO had changed a couple of the callipers and the brakes are now fantastic. I checked the engine mounts which are fine but I agree that at 70k I would be changing the clutch and doing those other things that get mentioned regularly -- new UAOS, IMSB, RMS, water pump, coolant stuff. Could be quite pricey. That apart, service annually with oil/filter change.. what more do you need. I also had the wheels refurbished which was not expensive and put on new rubber-- the old tyres were dated 2007 and 2009. Great improvement with much less harsh ride. Finally I run a little Garmin satnav with a wireless rear view camera which is most useful. Good luck with your acquisition, it sounds like a keeper. One note of warning -- you will find that gazing through the ads for shiny classics no longer holds the same appeal.

What a beauty. Congratulations! Start with the basics. Replace the brake hose w stainless items. Make sure the sunroof channel drains are clear, and check the firewall drains, they are easy to clean. Take off the bumper and clean the radiators. Do that every year after the leaves fall. welcome to classic sportscar ownership👍

OP - Beautiful C4S! Service records? I’ll add: At 75k the suspension needs assessment. Front transaxles, boots, seals. Last alignment? You can take it to someplace like CG if they aren’t too far away.

Thanks all for the really helpful replies so far. My project has started in earnest. Today I found some time to reblack the wing mirror houses and the windscreen cowl, it makes a big difference. I also got the car in stands and took the front wheels off. While the outside face of the front brakes were fine, the pic below is the inside face. It's the same on both sides. I'll check the rears and also pull the pads to have a look. Any thoughts on what this uneven wear could be caused by? The brakes also feel that they're dragging slightly, hough this could be the transmission on the 4, it definitely sounds like pads rubbing discs though.

Maybe stuck pistons but i think i would do a whole bunch of heavy braking stops to try and heat those calipers and rotors up. Kinda looks like its been sitting too long.

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Ill do some myself but clutch etc is beyond my skills and my garage. Got it for a good price though so have some cash to spare. Thanks, great tips. Its got all the stamps but not many invoices with details. It�s overdue a major service so lots of fluid changes coming my way. Ill try a bleed first as it�s too spongy to do a hard stop!

I imagine it does feel spongy given that the pad in that picture is contacting less than 1/2 the rotor!

In case you need a caliper rebuild and you or your indy can't do it. https://pmbperformance.com/products/...-restoration-1

With the uneven pad wear you are going to need new rotors and pads, but first get the calipers checked out.

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I experienced the same on a Mk 1 996 GT3 and a Cayman R. It�s pretty standard for a UK car. Opinions vary as what causes it, but washing the car and putting it away with wet discs seems to be high on the list. I think there�s also possibly an element of the plastic brake ducts guiding/forcing damp/wet air onto the inner face of the disc, that the outer face isn�t subjected to. If you wash the car, you should factor in a 10-15 minute drive afterwards to get sufficient heat into the brake discs to ensure they are bone dry before putting the car away. I�m doubtful there�s any fault with the calipers/pistons, but that should become clear when you retract the pistons back into the calipers to fit new pads along with the new discs.

+1 what Atgani said. Wrt lightweight flywheel you should do your due diligence regarding risk of ending up with a broken crankshaft. Imho the 4s is not the type of 996 to which a lightweight i.e. Single mass flywheel is best suited.

Congrats on the car--you'll love it. I acquired a 2002 C4S last year (mine's black, but seal grey is also a favorite color). As others have suggested there are standard wear items that probably need to be done or will need to be done in short order to a 20 year old car. Motor mounts and suspension should be high on your list of things to look at; plugs and coils, serpentine belt and pulleys, fluids, etc. If you're reasonably handy with a wrench, you can probably do those yourself. In servicing the brakes, I noticed a couple of torn CV boots--so a few more things to do while I'm under there. You'll probably find similar things. I took mine into an independent Porsche specialist and got a list of things needed. That was money well spent. Enjoy, AEP

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Thanks, hopefully up on stands properly tomorrow then we�ll see what we�re dealing with at the rear. I�m already planning on new plugs, so I�ll check the coils at the same time and the heat shields. . Front suspension arms look ok but the damper struts are corroding, the bump stops are shot which means I probably need to do the top mounts too. At least the coolant lines look good and someone�s been liberal with the waxoyl on the brake lines. Wish me luck for Friday evening!

Pulled the pads and found this. There's a step in the inside pad, matching the rust on the disc. So I think the pads are toast. Are the plates on the pistons supposed to be there? Usually I'd expect the pistons to push directly onto the pads, not onto a plate then the pads. They seem attached to the pistons, I don't know if this is rusted on or the actual part There's a step in this pad, which explains the step on the disc Rusty back

I think that plate is a brake pad damper. You will need to replace that as well/ It should have a male part that fits into the pistons. I was under the impression that there was a pad in each piston, but this one spans both. Hard for me to say until you pull that plate.

Got it. They are indeed male, found them on Design911 . More things to order! ​​

That is a thing with Porsche: you buy a bolt thinking it comes with the nut, but they are all separate parts. I was replacing the rear struts and you would think the nut for the top of the strut would also be in the box, and it is if you buy it from Bilstein, but if you get the Porsche part, you have to buy every single part. Bit of a pain really. We are all enjoying the pictures here.

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My '99 C2 has individual shims for the rear and the fronts are one piece.

The shims are intended to reduce brake squeal. Folks will happily sell you titanium shims that also reduce heat transfer from the pad into the caliper/brake fluid. I've always been curious if those actually help in anything other than race conditions.

Titanium brake dampers have a thermal conductivity about 25% of steel brake dampers, so the claim of heat transfer is technically true, but as a practical matter on a track where there are multiple times that heat is applied, I don't think it would matter unless your race was one lap.

Love that color and congrats on the car! I'd second 'wdb' and stick with the stock weight flywheel unless racing for two reasons. First, street driving smoothness will suffer and your idle might need a retune. I'm blessed to play with track cars daily (mostly american hardware, but some pcars) and when rotational mass drops a good bit, idle is frequently problematic, especially with AC on. Most track cars I encounter still have factory weight flywheel, certainly on street-driven cars. Love the pics, and it looks like you got ALL your money's worth out of the pads!! Keep updating us! Costas cars and such...

Why is the back of that one pad wet? Is that brake fluid? Carefully inspect for any leaks. I assume you intend to flush the whole brake system, not simply bleed it. Motive makes a bleed kit to make doing that pretty simple, but I do not put fluid into the Motive tank, just use it to safely supply the pressurized air to bleed the system. You just need to watch the reservoir to make sure it doesn't run dry and draw air. Depressurize the Motive before topping off the brake reservoir. Hawk makes excellent street pads that do not dust. Not sure where you go to get rotors, but in my experience, avoid cross-drilled rotors. The holes cause cracking in the rotors. I uses dimpled and slotted rotors, but I have a different car. After the brakes are sorted replace all the other fluids (oils, coolant, etc.). Coolant can be tricky due to trapped air. There are tools for correctly filling the system. Might be best to have an independent shop that knows these cars do that. Lastly, don't neglect the tires. If the car has been sitting a long time, the rubber could be dry rotted. A blowout at speed is not a good thing.

Thanks for the advice. A full fluid flush is definitely happening. The pad was wet as I'd had to use some penetrating fluid to get the pin out. Realising I was going to have to replace everything I got a bit liberal with it After traveling for work, I'm home tomorrow so the work starts to replace everything and bleed the brakes. Apparently the fluid was changed recently, probably not properly hence the the spongy pedal.