Welcome to 911UK
The only place for Porsche, 911uk is the definitive enthusiast and resource site for the Porsche 911.
Registration is fast, simple and absolutely free, so join up today for full access to the site and benefit from latest member offers.

Porsche Classifieds
Sell Your Porsche on 911uk
Create a Free Classified Advert
Search Ads
Classified Adverts FAQ
Trade Classified Information
Buyer & Seller Fraud Protection
Consumer Rights Act
Pre Purchase Inspection (PPI)
Porsche Car Sourcing
Porsche Cars Wanted
Official Porsche Centre Reviews
Model
Stock
Porsche 911
992 : 2019- 1
991 : 2011- 19
997 : 2004- 72
996 : 1997-2005 31
993 : 1993-1998 7
964 : 1989-1993 2
Carrera 3.2 : 1983-1989 3
Carrera SC : 1977-1983 2
930 Turbo : 1975-1989 1
Early 911 : 1964-1977 1
Porsche Other Models
Classic : 1950-1965 0
Boxster : 1997- 32
Cayman : 2005- 19
Cayenne : 2003- 6
Macan : 2014- 5
Panamera : 2009- 0
912-914-924-928-944-968 1
959 - CarreraGT - RaceCar 0
Car Parts For Sale & Wanted
Other Items For Sale & Wanted
Wheels Tyres For Sale & Wanted
Number Plates For Sale Wanted

Porsche Services
Porsche Body Shop Repair
Paint Protection & Wrapping
Porsche Classic Insurance
Porsche Classic Parts
Porsche Classic Restoration
Porsche Design Collection
Porsche Engine Gearbox Rebuild
Porsche Heritage & History
Porsche News
Porsche Picture Gallery
Win a New Porsche 911

Porsche Parts
Body Parts, Body Styling
Brakes, Clearance
Electrical, Exhausts
Engine Cooling, Engine Electrical
Engine Rebuild, Heating Cooling
Interior Incar, Lighting
Rubber Seals, Service Parts
Steering, Suspension
Transmission, Workshop Tools
Early 911, 911 - 930, 928 - 968
964 - 993, 996 - 997, Boxster
Cayman, Cayenne, Panamera

Porsche Model Range
911 [992] 2018-Current
Porsche 911 [992]
911 [991] 2011-2019
Porsche 911 [991]
911 [997] 2004-2012
Porsche 911 [997]
911 [GT] GT1-GT2-GT3
Porsche 911 [GT]
911 [996] 1997-2005
Porsche 911 [996]
911 [993] 1993-1998
Porsche 911 [993]
911 [RS] RS-RSR
Porsche 911 [RS]
911 [964] 1989-1993
Porsche 911 [964]
911 3.2 1983-1989
Porsche 911 3.2 Carrera
911 SC 1977-1983
Porsche 911 SC
911 [Early] 1964-1977
Porsche 911 [Early]
Boxster & Cayman
Porsche Boxster & Cayman
Cayenne & Panamera
Porsche Cayenne & Panamera

911uk Site Partners

Post new topic   Reply to topic
Author Message
Guywilko
Trainee


Joined: 04 Jul 2017
Posts: 56



PostPosted: Fri Oct 04, 2019 11:11 am    Post subject: Lost brakes at 100mph Reply with quote

Advice please

Oulton park track day. Brakes working really well. New brembo front disks, plenty of pad material front and back. Brake fluid 1 year old.

Carrera 4 with PSM. PSM on.

About 2 hours in, Car being driven by my mate who holds a MSA A licence - much faster than me and much more aggressive on the brakes.

Sudden loss of pedal - ie pedal went nearly to bulkhead!! We had a trace of brakes with pumping pedal but only at full pedal travel. Limped to pits.

I've had brakes fade out before and it deffo wasn't like that, they were great on one corner and virtually nil on the next. The pedal just travelled++.

In paddock checked the car over, no brake fluid loss on wheels. Brake fluid level at max. Took frunk plastic off. No leaks around master cylinder, ABS pump or PSM block. Calipers were hot but equally so. No disc blueing.

Bled the front brakes. No air in fluid. Fluid crystal clear.

After 20 mins brakes could be pumped to a decent pedal. After another 10 mins brakes felt normal. Took car for gentle run on the road. Brakes all good.

Went back on track, PSM off. Did about 3x 6 lap runs with 15mins cool down inbetween. Same problem re-occurred with me driving. Car cooled for 1h, we didnt bleed anything. brakes returned to normal with a bit of pedal pumping.

Drove home. Car feels normal.


?? Master cylinder seals, all advice / ideas welcome..

Guy
 
  
View user's profile Send private message
   
FZP
Estoril


Joined: 18 Jan 2015
Posts: 3737
Location: Cheshire


PostPosted: Fri Oct 04, 2019 11:14 am    Post subject: Reply with quote

Boiled the fluid by the sounds of it.
_________________
997.2 Carrera 2S GT Silver/Cocoa.
 
  
View user's profile Send private message
   
Luddite
Nürburgring


Joined: 18 Dec 2018
Posts: 463
Location: Scotland


PostPosted: Fri Oct 04, 2019 11:21 am    Post subject: Reply with quote

Boiled brake fluid is my guess, perhaps you have a slightly sticking pad/caliper/ piston.

Have not a clue on the ABS/electronictrickery etc.etc. but would bet on fluid boiling... Been there done that and got away with it too.. Very Happy

Hopefully there will be some smarter folks who will provide alternatives for you in time. Thumb
 
  
View user's profile Send private message
   
996ttalot
Approved Trader


Joined: 21 Sep 2009
Posts: 1497
Location: Horley Gatwick


PostPosted: Fri Oct 04, 2019 11:51 am    Post subject: Reply with quote

What you have described is normal in the sense of the fluid boiling. That can be down to several factors including whether you are riding the brakes for too long e.g. drivers who coming to a bend brake far too early and on the brakes for longer instead of braking later for less time.

But you need some proper fluid SRF etc in there and also probably some brake ducting to help keep everything cool.

As an example a non GT3 Porsche driven well you can loose the pedal within 20km on track without proper cooling and fluid.

The other point to mention is that many people think that upgrading brakes in itself is enough - on the road they say how great they are etc, but take on track and all of a sudden brakes getting hot. If you think of it in simple terms, if you have a larger disc in the same wheel housing, without changing the airflow, you are actually going to have more heat. That is why when we upgrade brakes, we also do the air flow at the same time.

Ken
_________________
nineexcellence.com
Tel: 01293 226911. Follow us on Facebook www.facebook.com/Nineexcellence
SALES, SERVICE, UPGRADES
 
  
View user's profile Send private message Send e-mail Visit poster's website
   
Martin996RSR
Nürburgring


Joined: 08 Dec 2016
Posts: 385



PostPosted: Fri Oct 04, 2019 3:23 pm    Post subject: Reply with quote

My C2 brakes did more or less the same thing during a track day at Bedford. It was obviously boiling fluid. I have brake ducts but they're the standard rather than GT3 ones, and my fluid was old and the longer it's in there, the more water it absorbs from the atmosphere, and the lower its boiling point becomes.

If you put on bigger brakes then you're dissipating the same amount of heat energy for the same 'stop' through more mass (via bigger calipers and discs) and radiating out that heat across bigger surface areas. Because of that, bigger brakes will have less of a propensity for boiling fluid if they're bigger.

If you don't have several grand lieing around to pay for a big brake upgrade, then buy the highest boilingpoint fluid you can find and then put the larger GT3 brake ducts on. They're cheapest from your OPC, believe it or not.
 
  
View user's profile Send private message
   
skinny_monkey
Nürburgring


Joined: 16 Sep 2014
Posts: 443



PostPosted: Fri Oct 04, 2019 4:40 pm    Post subject: Reply with quote

Boiled fluid.
Change brake ducts for GT3 and fluid for something like RBF 600/660 type or SRF if your wallet extends.
 
  
View user's profile Send private message
   
The return of Marty Wild
Kyalami


Joined: 04 Nov 2016
Posts: 1828



PostPosted: Fri Oct 04, 2019 7:17 pm    Post subject: Reply with quote

I had the brakes go at the end of the extended straight at Bedford, the discs were in poor state and as deMort pointed out, were mounted on the wrong side of the car. I took to the grass and took a lap or two with my tail between my legs. Car had the GT3 ducts. I do accept I probably was sitting on the brakes for too long.

Anyways, replaced the discs and pads with Brembo items. Gave the calipers as good as service as I could to try regain lost functionality. Finally had racing fluid put in.... no brake issues when I returned.
_________________
Life's too short for cr4ppy cars, keep it German!

Boxster S 986.1
Cayman S 987.1 (gone but not forgotten)
 
  
View user's profile Send private message
   
Mac996t
Montreal


Joined: 26 Mar 2011
Posts: 501


2004 Porsche 996 Turbo

PostPosted: Fri Oct 04, 2019 7:36 pm    Post subject: Reply with quote

I’ve boiled brake fluid a few times at Oulton and each time it was obvious it was going to do it due to the pedal travel getting longer over a few corners.

That’s the bit of your experience I don’t get, one corner fine then the next gone, seems a bit too quick, also any time I’ve boiled the fluid everything been seriously hot and smelling strongly of burning brakes and the discs have a fair bit of colour to them?

The rest of your experience does match ie the recovery back to normal when allowed to cool?

Mac
 
  
View user's profile Send private message
   
Guywilko
Trainee


Joined: 04 Jul 2017
Posts: 56



PostPosted: Sun Oct 06, 2019 7:49 am    Post subject: Reply with quote

Thanks everyone for your experience and wisdom.
High temp fluid and GT3 ducts on order.
Any advice on pads for track day use?
 
  
View user's profile Send private message
   
Y2K
Montreal


Joined: 08 Mar 2016
Posts: 520
Location: Hampshire


PostPosted: Sun Oct 06, 2019 8:06 am    Post subject: Reply with quote

I experienced brake issue on my very first track day in a 911 (996 C2); soft pedal, suspected boiled fluid.

It turned out that as I was braking, the outside of my foot was catching the throttle ever so slightly (thus braking with throttle on); this wasn’t picked up by myself as it was masked by H&T downchange.

Then I had the opportunity to spend some time with an instructor, and he pointed out my problem straight away. The 996 was my first car with floor-hinged pedal hence my issue.

Since then no more problem; the humble C2 has superb brakes.
_________________
2005 996 GT3 mk2
1999 Integra DC2
 
  
View user's profile Send private message
   
Y2K
Montreal


Joined: 08 Mar 2016
Posts: 520
Location: Hampshire


PostPosted: Sun Oct 06, 2019 8:12 am    Post subject: Reply with quote

Guywilko wrote:
Thanks everyone for your experience and wisdom.
High temp fluid and GT3 ducts on order.
Any advice on pads for track day use?


When I had my C2 I used Pagid RS-5 which has since been discontinued. I guess any Pagid RS line would be fine (RS-29 the best but might be overkill and some experienced squealing for road use)
_________________
2005 996 GT3 mk2
1999 Integra DC2
 
  
View user's profile Send private message
   
Clanky
Österreich


Joined: 24 Aug 2012
Posts: 968
Location: Scotland

2007 Porsche 997 Turbo

PostPosted: Sun Oct 06, 2019 3:10 pm    Post subject: Reply with quote

If you can get pads to fit, Ferodo DS2500 are superb pads.
Instant bite, no noise & very little fade.

For you to loose brakes that quickly, it defo sounds like boiled fluid or the heat affecting the master cylinder seals.
_________________
996 C4s (Gone)
997 Turbo

S3 Daily Driver
 
  
View user's profile Send private message
   
maldren
Suzuka


Joined: 07 Oct 2016
Posts: 1162



PostPosted: Sun Oct 06, 2019 4:46 pm    Post subject: Reply with quote

There is always a lot of discussion here about upgrading brakes and there's a number of reasons for doing it. The usual reason on the road is for improved pedal feel - more bite like a typical modern road car. The standard brakes have plenty of stopping power for road use.

For track use the major problem is that brakes overheat on repeated use. Not a problem you should ever see on the road unless, perhaps, you descend an alpine pass very quickly in a high gear. There are typically two different symptoms of this depending on the brake setup:

1. Fade is where the pads lose performance at higher temperatures, pads that have good characteristics for road use (bite, friction levels wear rates etc.) are not set up for high temperatures and lose performance when they get hot - fade. This can be terminal for the pads as they can become 'denatured' as some of their core materials can be burned off, permanently damaging the pads.
Track pads are designed for high temperature use and often work poorly at low temperatures and are therefore not good on the road. You've probably seen disks glowing red/white hot on formula one cars.

2. Fluid boiling. What it says, too much heat boils the fluid. There can be other heat related issues as well. Disks can get red hot and rubber and plastic parts can be damaged, not good. Disks designed for road use can also become distorted at higher temperatures than they are designed for.

On the track, it's a matter of dissipating the heat. Bigger disks can hold more heat but as above, the heat still has to be dissipated. They basically hold more heat and delay the point at which the temperatures become too high but this may not be a solution on the track. They are also heavier, not a good thing on the road or track. Their larger surface area does aid cooling but only if there is enough airflow around them.

As Ken says, ventilation is the key. Ventilated disks cool better than solid ones but the answer is to get air across the disks (see formula 1 ducting!)

Carbon disks etc are a whole level above this!
_________________
Mike
2003 996.2 C2 Coupe Arctic Silver
 
  
View user's profile Send private message
   
uk996
Monza


Joined: 09 Jan 2018
Posts: 162
Location: Home Counties


PostPosted: Mon Oct 07, 2019 11:31 am    Post subject: Reply with quote

When I went underneath my car, I saw the ducting already installed. Didn't know the GT3 had more effective ducting. So it's worth changing to get more air flow. I've seen that some people cut vents in the wheel arch lining to do this too.
_________________
2002 996tt Aero in seal grey 6MT
 
  
View user's profile Send private message
   
Luddite
Nürburgring


Joined: 18 Dec 2018
Posts: 463
Location: Scotland


PostPosted: Mon Oct 07, 2019 2:29 pm    Post subject: Reply with quote

Thanks maldren, you answered the question I was just about to ask relative to racing pads for road use, I had wondered if that situation had changed/improved with new pad materials......NOT that I am into that sort of stuff now, just that in my yoof I used to think race ANYTHING was an improvement on my bikes and later cars, it took some time and a fair bit of cash to realise that altering the all important balance of a machine designed for the road by fitting /tuning to pure race spec could be a real disappointment. As you typed cold race spec pads can be a pain in the rear or worse on the road, especially in the wet and cold in stop go traffic...hmm...?
 
  
View user's profile Send private message
   
MaxA
Albert Park


Joined: 11 Oct 2015
Posts: 1616
Location: Helsinki


PostPosted: Tue Oct 08, 2019 8:25 am    Post subject: Reply with quote

Y2K wrote:
Guywilko wrote:
Thanks everyone for your experience and wisdom.
High temp fluid and GT3 ducts on order.
Any advice on pads for track day use?


When I had my C2 I used Pagid RS-5 which has since been discontinued. I guess any Pagid RS line would be fine (RS-29 the best but might be overkill and some experienced squealing for road use)


I run Pagid RS29s - even in the winter and I'm not dead yet, even if they are compromised for road use (they just need a little heat).

Of course extreme braking in the winter is pretty much a bad idea as it is so easy to overwhelm the tyres and some degree of finesse is required.

And for the record, I run Motul RBF600 brake fluid and change it annually. I have not had any issues with stopping on the track with this set up. It's no fun boiling your fluid... what
_________________
997.2 Carrera4S: white over blue, driven and tracked, seldom clean.
 
  
View user's profile Send private message
   
wasz
Sepang


Joined: 28 Dec 2012
Posts: 2981


1999 Porsche 996 Carrera 2

PostPosted: Tue Oct 08, 2019 2:23 pm    Post subject: Reply with quote

Clanky wrote:
If you can get pads to fit, Ferodo DS2500 are superb pads.
Instant bite, no noise & very little fade.

For you to loose brakes that quickly, it defo sounds like boiled fluid or the heat affecting the master cylinder seals.


+1 to Ferodo ds2500. Decent pads will help with the heat too.

I have also lost the brakes like that on track as a novice, this was in a brand new road car (mfr jolly) that did not end quite so well....

I also boiled the brakes on my 996 brake on the first track day when I got it (old fluid), but it was more noticeable. I soon re-bled them with decent fluid.
_________________
My special order MY99 Vesuvious Charcoal 996 | Clutch, Fly RMS IMS AOS Job |
Steering Rack Hard Lines | Air Con Compressor / System
 
  
View user's profile Send private message
   
maldren
Suzuka


Joined: 07 Oct 2016
Posts: 1162



PostPosted: Tue Oct 08, 2019 2:45 pm    Post subject: Reply with quote

[quote="wasz"]
Clanky wrote:
I also boiled the brakes on my 996 brake on the first track day when I got it (old fluid), but it was more noticeable. I soon re-bled them with decent fluid.


Yes, old fluid is the worst. It's hygroscopic (it absorbs water) and the water boils at only 100C, a much lower temperature than brake fluid which is more than twice that. You can easily reach 100C on the road so change any old fluid you have and don't be tempted to use fluid that has been sitting opened on the garage shelf.
_________________
Mike
2003 996.2 C2 Coupe Arctic Silver
 
  
View user's profile Send private message
   
jcharalambides
Newbie


Joined: 14 Jan 2019
Posts: 35



PostPosted: Wed Oct 23, 2019 3:30 pm    Post subject: Reply with quote

For what its worth, i run Brembo HP2000 pads with standard discs, braided hoses and high temp brake fluid and have had no issue on track.
Did 124 laps of brands indy last month and not one issue with brakes.
The brembo pads don't squeal on road also which is good.
 
  
View user's profile Send private message
   
Display posts from previous:   
Post new topic   Reply to topic   All times are GMT - 12 Hours
Page 1 of 1

 
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum
You cannot post calendar events in this forum