DJ23

Has anyone had any issues with the PCCB's in the rain? Last night I was stuck in a down pour coming home from a Porsche meeting of all things and was driving along the highway and had to apply the brakes with slowing traffic. My first reation was of great concern. Where was that grab and dig that I get on dry days? After pumping the pedal several times they grabbed as they usually do, but what a scary situation. Here I am driving along, not fast mind you, and feeling secure with my ceramics, and wow, there was nothing there. Thank goodness there wasn't anyone directly infront of me. The only thing I could think of is that these brakes react better when dry and hot. The rain probably cools them, and with them being wet, they take a little pumping to react within normal parameters.

Anyone else experience similar situation in the rain or when brakes are wet?

Jay

jcnesq

Your experience is exactly the same as mine, and the first time it happened with my 05 S it scared me silly. They do grab of course after a relatively short delay, but it was nothing I had ever experienced before with steel brakes. Since then my solution is to tap the brakes now and then when driving in heavy rain.

There are some older threads on this which you will find with a search, and maybe even an occasional doubter that this "problem" exists. But there is no doubt in my mind at all that this can and does happen with PCCB's.

Terry Adams

Yes. Scary the first time.

https://rennlist.com/forums/997-turb...ain-again.html

DJ23

Thanks for the reply. At least I wasn't imagining things, or, it was just me. This is something that needs to be addressed in future renditions. I'll always be cautious in the rain from now on.

Jay

E55AMG

yep, same here. first time was interesting to say the least. If cruising on the highway in the rain I just tap the brake every now and then

Macster

Some cars (Mercedes?) under some conditions (wipers on?) will periodically apply the brakes. Not enough to slow the car and probably not enough to cause the brake lights to come on (or the brake lights are disabled during this process), but to simply 'dry' the pads/rotors so the brakes bite earlier in the wet.

Another scheme is under some conditions like if the throttle pedal is suddently released and the brake applied a system applies extra initial pressure to the brakes to get the braking going sooner.

Sincerely,

Macster.

w00tPORSCHE

With my frequent visits to the Seattle/Portland area that answers my long time question (and itch) on whether to upgrade to PCCB's or not on my next 911.

MadScience

So I had this experience again yesterday. Except this time I could slowly count to 5 before anything happened at all. Which was much worse than my precious experiences that were perhaps a second or so.

It was an absolute downpour and lots of traffic kicking up even more water, which of course dumps through all the brake ducting. If I understand things correctly then it's not an issue with water being present, but it preventing the usual instant temperature spike that'll bring the brakes into operating range. I ended up switching lanes while on the brake and was lucky to have plenty of room to slow down in the other lane.

However it's really made me think twice about daily driving this car in potential heavy rain in traffic. Perhaps I should switch to steel rotors in the winter? Yes, I can try to remember to touch the brakes regularly enough to keep them from going dead cold, but I'd clearly forgotten this lesson from last year and learned it again in a much more scary, though still non-consequence way.

I really don't want to have to make a statement to an insurance company someday to the effect that my $15k brakes simply sometimes don't work in the rain.

I live in CA, just not driving in rain is almost an option, and I usually just drive my van when it does to cut down on having to wash the turbo. But do PCCBs really make this a fair weather car?

I suppose if I lived in the midwest or the southeast or somewhere else with regular heavy rain, I could afford the garage space for a fourth car. So the sample size of folks that are truly forced to daily drive with carbon ceramics might not be that large yet, despite the fact that they are becoming more available.

Berra

I have this sometimes with my 996TT, but I apply the brakes very very gentle from time to time when driving on the highway to keep them dry.

This is in fact something that ordinary steel brakes can suffer from too. I'm in Sweden and we get to learn this when taking the drivers license.

Some cars/brands have the feature where the car brakes by itself to keep the brakes dry, nothing you as a driver or passenger will notice but it's there.

RJKflyer

Yes on my 2006 B7 RS4 the brakes were periodically and very slightly applied by the ESP 8.0 system in the rain. I don't know but assume the 'trigger' was the rain sensor (wipers no good as that's a driver decision).

I cannot find any reference to this in Porsche technical literature, but can't believe this isn't present on our cars?

96_993TT

Yes, same experience here. I just use caution if caught in the rain and apply the brake lightly occasionally when wet. My friend who had a 14 TTS and now a 17 TTS said they fixed that issue in the 991. The brakes are lightly pumping on the rotors when not being applied. Sounds crazy but they did something to fix this in the 991.

MadScience

So perhaps the 996/997 era cars are outliers.

We have a diesel 3 series wagon that does the automatic drying as well with steel rotors. I've experienced just a moment of the same sensation with other steel rotor'ed cars as well, but it's much much shorter. This was more along the lines of having boiled the fluid (but of course with a firm pedal), in terms of the amount of time it took to get things to start to act like a brake again.

hds10

Yes, had the same experience with my 997.1TT but not with the 991TTS. Porsche must have fixed the issue.

993MAN

All I can say after reading this thread is I'm glad my s##tty old steel brakes work in any conditions!

That is just BS given the expense of the things.

sexfiend

Can anyone with 991+ cars with PCCB confirm that this behavior doesn't happen anymore when it is raining?