991 generation PCCBs in very wet conditions
Discussion
Hi all,
Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
evilandy said:
Hi all,
Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
I have drove my 991GT3 round Silverstone when the hanger straight has been a river...Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
Never ever had this problem, Same for TTS
sounds like you may have something stuck between the pad and disc....I would get an OPC to check, though, has your car done around 4k miles by any chance?
Hi Andy, yes, I have experienced this, just something I've got used to, also the same after a car valet, I guess under certain circumstance it could catch you out and potentially be very dangerous, guess they could do with a wiper like some brake systems. Anyway, enjoy, lot of crap flying about on this forum at present
Edited by jh001ace on Tuesday 31st March 21:43
Hi Andy, yes, I have experienced this, just something I've got used to, also the same after a car valet, I guess under certain circumstance it could catch you out and potentially be very dangerous, guess they could do with a wiper like some brake systems. Anyway, enjoy, lot of crap flying about on this forum at present
Edited by jh001ace on Tuesday 31st March 21:44
So I'm guessing they don't have self drying brakes?
My E46 330Ci was shocking in the wet - had a 330Cd and that was exactly the same. Turns out the SE models were fine but the sport models had different ducting on the front bumper which meant the brakes did nothing in the wet when first applied. The next generation 3 series had self drying brakes on the 6 cylinder variants so I guess BMW knew it was an issue. Sorry this doesn't help however!
My E46 330Ci was shocking in the wet - had a 330Cd and that was exactly the same. Turns out the SE models were fine but the sport models had different ducting on the front bumper which meant the brakes did nothing in the wet when first applied. The next generation 3 series had self drying brakes on the 6 cylinder variants so I guess BMW knew it was an issue. Sorry this doesn't help however!
L
evilandy said:
Hi all,
Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
Yes I have experienced this on a very wet motorway drive a few years back in my 997 turbo s with PCCB. I think it's a characteristic of these brakes and yes bloody scary when u first experience it. Just need to be careful in very heavy rain I guess.Wanted to do this as a poll but couldn't work out how.
This Sunday I had to drive up the M6 to Scotland in some of the most dreadful torrential rain I can remember. Driving a 991 GT3 with PCCBs. On several occasions I applied the brakes only to be greeted by almost zero response. The feeling was one of no brake grip accompanied by a sound a bit like metal on metal. After maybe 5 seconds of application they would eventually start to bite.
It was so bad that when I stopped for coffee I googled the possible problem and there are lots of discussions on PCCBs in the wet. Some claiming the problem only exists on older versions. Some denying the problem at all. Some recommending doing some test braking every now and again.
I've had similar issues when starting off after leaving the same car outside in the rain overnight. However it usually cleared up after a single test-brake to dry out the brakes. In this circumstance I think its ok to have to dry the brakes out before setting off. However on this journey the rain was continuous and heavy and the problem was persistent, maybe returning every 10 to 15 minutes. It seems impractical to test brake every 10 to 15 minutes, and what happens if there was an emergency in between drying out?
Just wondering how widespread this issue was. It seems very dangerous to me. Almost too bad for Porsche to have released the car with this fault. So wondering if I have an isolated problem or if others have had similar experiences?
FYI, I've driven hundreds of cars and I've had my license far longer than I care to remember. So I'm used to cars with old/bad breaks. However I've never experienced an issue as bad as this before.
Andy
The reason might not actually be directly related to the wet weather.
By that I mean that the problem may not be water between pad & disc. But instead that the water has cooled the disc to such a degree that the brakes need more than the normal prod to bring them up to operating temperature, before giving any effective braking.
It's just a thought.
Kyri
By that I mean that the problem may not be water between pad & disc. But instead that the water has cooled the disc to such a degree that the brakes need more than the normal prod to bring them up to operating temperature, before giving any effective braking.
It's just a thought.
Kyri
I used to get this issue with the PCCBs on my 997 - it did give me a wee fright too the first time it happened. Seemed to be the combination of wet and cold that brought it on. Not sure if ceramics are particularly susceptible to it or if it's just they are so good when warm and dry the contrast is more striking. I found the solution was to give them a quick dab every so often. If the problem arose then coming off the brakes momentarily and then getting back on them hard worked well. Many of the brake assist systems now have an 'auto-dry' function - Audi/Merc/BMW have had it as standard on several models for a few years now - surprised it's not on the 991.
Edited by Oso on Tuesday 31st March 23:51
Oso said:
I used to get this issue with the PCCBs on my 997 - it did give me a wee fright too the first time it happened. Seemed to be the combination of wet and cold that brought it on. Not sure if ceramics are particularly susceptible to it or if it's just they are so good when warm and dry the contrast is more striking. I found the solution was to give them a quick dab every so often. If the problem arose then coming off the brakes momentarily and then getting back on them hard worked well. Many of the brake assist systems now have an 'auto-dry' function - Audi/Merc/BMW have had it as standard for a few years - surprised it's not on the 991.
Pretty sure the Gen 1 997 C4S had brake 'pre-fill' or something to deal with this. Assumed it would be standard on the 991.cslwannabe said:
My E46 330Ci was shocking in the wet - had a 330Cd and that was exactly the same.
I also have an E46 330Ci and was driving into Brighton in normal rain for a while without touching the brakes at all. As I was coming up to the big roundabout at the end of the A23, I almost shat my pants as I pressed the brakes and nothing happened. Took a few seconds and then they started to bite. But holy cow, my heart was racing for a while after this experience.cslwannabe said:
The next generation 3 series had self drying brakes on the 6 cylinder variants so I guess BMW knew it was an issue.
That is indeed true.Similar on my 7.2 GT3. It is really bad when coming straight out of the car wash. Braking performance is massively reduced and it needs six, seven proper braking attempts to disappear. On the road I had this only once so far. It was just a few days ago in torrential rain in the early morning. Scary...
Dr S said:
Similar on my 7.2 GT3. It is really bad when coming straight out of the car wash. Braking performance is massively reduced and it needs six, seven proper braking attempts to disappear. On the road I had this only once so far. It was just a few days ago in torrential rain in the early morning. Scary...
Yep, same for me! Its only after a car wash though, never in rain no matter how heavy the fall is.
Oso said:
Many of the brake assist systems now have an 'auto-dry' function - Audi/Merc/BMW have had it as standard on several models for a few years now - surprised it's not on the 991.
I know my R8 has this function and the ceramic brakes are fine in very wet weather. After having the car washed the brakes are terrible with the first use so I assume this auto dry system is linked to the auto wiper sensor for the car to know when it's raining.I would think Porsche would have a similar system as I wouldn't want to be using ceramics without it! Maybe a call to your OPC would clear this up.
Pre-fill is not connected with disc drying. Pre-fill pressurises the brake system and moves the pads closer to the discs, in preparation for a firm stop, triggered by an abrupt throttle release.
I've had low braking action after a thorough wheel dousing / hosing from cleaning in a 991 TTS and F10 M5. "Perturbing" when it happens, accompanied with "oh, shoot" or similar. I haven't experienced it in normal rainy driving. But if it is cured by some braking action, that would suggest that is the problem, and it could, if P want to for future models, be cured by using a Bosch disc drying software add on in the ABS module a la Mercedes or BMW.
I've had low braking action after a thorough wheel dousing / hosing from cleaning in a 991 TTS and F10 M5. "Perturbing" when it happens, accompanied with "oh, shoot" or similar. I haven't experienced it in normal rainy driving. But if it is cured by some braking action, that would suggest that is the problem, and it could, if P want to for future models, be cured by using a Bosch disc drying software add on in the ABS module a la Mercedes or BMW.
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