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Leaking Cabriolet Roof - 2005 997

John RS

New member
Joined
26 Apr 2019
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3
Hi all, just bought my first 911 which has done 90,000 and is a C2 2005. Love it but horrified with the amount of work the Porsche specialist has highlighted - beginning to understand it is a question of prioritization. BUT just discovered the cabriolet roof is leaking somewhere into the passenger rear footwell and it's been making the electrical control box there wet and the circuit board is corroded.

Is there a typical leak source and is it going to be expensive for specialist to fix?

If I need to get a new circuit board, part number 997 618 260 04 is it a straight plug in or does it need to be coded etc?

John
 
Sounds more like it's your rear drain that's blocked and not the roof. There's a drain on either side that runs down between the out skin and the internal trim. The drain can become blocked at the bottom behind the rear wheel arch liner. If you remove the front part of the liner you'll see the drain. Poke it with something and all the gunk will no doubt come flooding out.
 
:welcome:

Not very helpful I know but well done for joining up :thumb:
 
The control unit will be the rear control unit .. if the car still starts then you are lucky as they often don't.

if you have parking sensors then i'm afraid the control unit is next to the rear cu and will also be damaged .

Both of them HAVE to be coded on to your car .

Leak has been explained by Alex but a couple of images to help you below .. i would advise you to also remove the rear speakers each side , the plastic panel and make sure there are no leaves etc also blocking the drains .

You need to remove the arch liners to get access to this drain ... its only a couple of screws though .

Throw that rubber grommet away and blow up the tube with an airline .
 

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Yep drain holes, I had the same thing when I bought my garage queen 911 last year. Had local mechanics clear them out for me since I'm rubbish with spanners. Think it was under an hour of labour. Had to take up the carpets and dry it all out since the sound deadening is like a 2 inch thick massive sponge. It's dry now but had to have them up for a few weeks. Plus also bought some car dehumidifier packs of eBay to make sure the remaining water was absorbed from the air.
 
I used a VAX carpet cleaner to suck the majority of water out the carpet/foam. Then leave something underneath it to let air circulate. I used a paint tin. Leaving a household dehumidifier in running overnight also helps.
 
Thanks, all. I took it to the local Porsche specialist on Saturday and they half opened the cabriolet roof and looked at the drains from the top....it all looked quite dry and no debris. They didn't try to do anything around the drain bungs in the wheel arch although they did blow some air down the side in question and no blockage perceived.

What they discovered was that the seals in the passenger door were shot and concluded this is how the water got in under the passenger seat and rear footwell.

So I have booked it in to have both doors re-sealed - I will ask them to double check drain under the wheel arch as you advise.

£543 incl VAT to get a new rear control unit and code it. The current one is massively corroded so I think this is historic damage.....am talking to the Dealer I bought it from as I think this is not fit for purpose (I only bought it a month ago!) - any views on that?

Cheers, John
 
Those units corrode in minutes so I very much doubt this has happened over time. I had a similar problem with an Audi. Ended up writing it off.

I'm also not convinced with their diagnosis. Did they sit in the car with a hose pipe on it and watch where the water came in? Doubt it.

Good luck but I can see this headache coming back.
 
Thanks, guys. I really appreciate your suggestions. Can I get the wheel arch covers off with the wheel still on? Would try and check it myself if I can, but if not will ensure the garage does.

Interesting about the circuit board degrading in minutes? Will post a pic when I receive it from the valeter who "discovered" the leak!

I think I will get the doors resealed and get the garage to do the hose test BEFORE I pay for a new CU, given it is working at the moment.

Cheers, John
 
This was mine. The corrosion is created by the electrical charge under water.

The front part of the arch liner can be pulled back once the plastic rivets in it are removed. This will then expose the drain plug so you can check it.
 

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John RS said:
Thanks, guys. I really appreciate your suggestions. Can I get the wheel arch covers off with the wheel still on? Would try and check it myself if I can, but if not will ensure the garage does.

Interesting about the circuit board degrading in minutes? Will post a pic when I receive it from the valeter who "discovered" the leak!

I think I will get the doors resealed and get the garage to do the hose test BEFORE I pay for a new CU, given it is working at the moment.

Cheers, John

If everything is working then it would seem ok to me .. and i've changed a few over the years :wink:

Its just about possible to remove the liner but you need very shallow tools to do it with the wheel in situ ... i always remove the wheel .

The door membrane does not tend to create this problem .. its 99% of the time the rear drains blocking which ends up flooding and there by destroying the control units .

If you have Bose then i believe the control unit is under the drivers seat .. that or phone module depending on the gen it is ... so that side getting wet will kill them .

The corrosion is normal and as Alex says .. electricity in water causes it .. is it Osmosis ? .. not sure of the word to be honest .. electrolysis perhaps .

Either way its toast if it happens .
 
John RS said:
Thanks, all. I took it to the local Porsche specialist on Saturday and they half opened the cabriolet roof and looked at the drains from the top....it all looked quite dry and no debris. They didn't try to do anything around the drain bungs in the wheel arch although they did blow some air down the side in question and no blockage perceived.

What they discovered was that the seals in the passenger door were shot and concluded this is how the water got in under the passenger seat and rear footwell.

So I have booked it in to have both doors re-sealed - I will ask them to double check drain under the wheel arch as you advise.

£543 incl VAT to get a new rear control unit and code it. The current one is massively corroded so I think this is historic damage.....am talking to the Dealer I bought it from as I think this is not fit for purpose (I only bought it a month ago!) - any views on that?

Cheers, John

Is there water on both sides at the rear? If so the passenger seal probably isn't the problem, on only part of it. It sounds so similar to my issue and mine was simply clogged drains since the problem has not re- appeared since. I made sure the garage left the caps off the ends of the drain holes when they put it back together too since these are probably the main culprit as to why they get blocked in the first place.
 
Any Porsche specialist should know this as its a very common problem.
 

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