911 Brake Vibration

Nuclear Nick · Post by **Nuclear Nick** » Wed Nov 13, 2019 7:37 am

I've just got my 911 back after a fairly lengthy period at the OPC while a strong vibration under braking was investigated. Eventually all four discs and pads were replaced before the issue was resolved.

It feels like a different car now so, although the vibration has been significant recently and easy to demonstrate, I believe it has been developing slowly over about 12 months. I first noticed a slight vibration under light braking at motorway speeds around September last year. The OPC investigated but could not identify an issue. Forward 12 months and I found that the vibration could be reproduced by deliberately heating up the brakes, such as carrying out hard braking to clean and bed the pads and discs. The vibration could be felt through seats and floor, rather than the steering and pointed to an issue with the rear brakes. The technician started with disc runout measurements all round, albeit with cold discs. One rear disc was found to be borderline out of spec and the diagonally opposite disc borderline within spec.

To cut a long story short, it seems that having to adhere to Porsche's strict protocol for brake investigations, particularly under warranty, a step by step, one disc at a time, process had to be followed. Although the two discs with slight runout had been replaced the vibration remained and it was not until all four were changed that the vibration finally ceased.

The OPC tell me it is very rare for a 911 to suffer a brake fault of this extent, especially at this age and mileage, that requires all the discs to be changed. It is not clear exactly what the fault was since runout and rolling road measurements were somewhat inconclusive, hence the trial and error approach. But at least it is now cured and the car feels so different, just as it should feel under all levels of braking. The smile is back on my face!

VanB · Post by **VanB** » Wed Nov 13, 2019 7:41 am

You haven’t had much luck with the car it seems. Hopefully no further problems from here on in.

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MacanArif · Post by **MacanArif** » Wed Nov 13, 2019 7:55 am

Glad it's back with you now, on the positive side all of these things have happened while the car is under warranty.

Wing Commander · Post by **Wing Commander** » Wed Nov 13, 2019 8:00 am

Glad to hear that your smile is back, Nick!

Paul · Post by **Paul** » Wed Nov 13, 2019 8:40 am

Rab J · Post by **Rab J** » Thu Nov 14, 2019 7:46 pm

Glad to hear you got things sorted Nick. Brake issues aren't nice and can spoil things quickly. Luckily

I haven't any such issues with mine yet but then I've only 5k on it so far. At what mileage did you first notice the vibration?

Wing Commander · Post by **Wing Commander** » Thu Nov 14, 2019 8:39 pm

About 23k miles on mine now, with no brake issues, but I do just have the standard Carrera brakes

Paul · Post by **Paul** » Thu Nov 14, 2019 9:50 pm

Rab J wrote: ↑Thu Nov 14, 2019 7:46 pm At what mileage did you first notice the vibration?

..when trying to keep up with a Red Audi TTS Cab down various French “Cols”..!

Nuclear Nick · Post by **Nuclear Nick** » Fri Nov 15, 2019 7:48 am

Paul wrote: ↑Thu Nov 14, 2019 9:50 pm
Rab J wrote: ↑Thu Nov 14, 2019 7:46 pm At what mileage did you first notice the vibration?
..when trying to keep up with a Red Audi TTS Cab down various French “Cols”..!

Yes, used the brakes a lot 'cos it was so slow!

Nuclear Nick · Post by **Nuclear Nick** » Fri Nov 15, 2019 7:51 am

Rab J wrote: ↑Thu Nov 14, 2019 7:46 pm Glad to hear you got things sorted Nick. Brake issues aren't nice and can spoil things quickly. Luckily I haven't any such issues with mine yet but then I've only 5k on it so far. At what mileage did you first notice the vibration?

Around 6k Rab. It's on 12k now.

911 Brake Vibration

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