Why change your Cays brake fluid?
10-19-2004, 12:25 AM
#1
Rennlist Member
Thread Starter
Why change your Cays brake fluid?
As some may have noticed in this forum I particularly enjoy taking my 5000lb porsche truck to DEs. This has worked out well for me (read safe and alot of fun) but has met with mixed reviews (read who cares!). Anyway the race car guys in this forum have been honest in their views and also very helpful and knowledgable.
My only problem at the track with the cayenne has been boiling the brake fluid. According to the laws of thermodynamics this is not a suprise. This weekend Im going to Moroso (fun right!) and have changed my brake fluid to castrol SRF at the recommendations of the race car guys (smart bunch).
Anyway, the stuff cost $65 a liter and only comes in a liter. The cay takes probably a little more than that for a complete flush. My question then is this (sorry if this is in the racing threads) if you open a liter of SRF and dont use it all does it go from its dry to wet boiling point or is it just not good for latter use?
Will you racers give me some suggestions with this stuff?
My only problem at the track with the cayenne has been boiling the brake fluid. According to the laws of thermodynamics this is not a suprise. This weekend Im going to Moroso (fun right!) and have changed my brake fluid to castrol SRF at the recommendations of the race car guys (smart bunch).
Anyway, the stuff cost $65 a liter and only comes in a liter. The cay takes probably a little more than that for a complete flush. My question then is this (sorry if this is in the racing threads) if you open a liter of SRF and dont use it all does it go from its dry to wet boiling point or is it just not good for latter use?
Will you racers give me some suggestions with this stuff?
10-19-2004, 11:18 AM
#2
Super Moderator
Needs More Cowbell
Lifetime Rennlist
Member
Needs More Cowbell
Lifetime Rennlist
Member
Tom,
Most PCA DE regions require that the brake fluid be flushed/changed once per year, in addition, bled prior to each event:
http://www.porschenet.com/DE_PDF_WordFiles/TechForm.pdf (example)
Some brake fluids (Motul 600 IIRC) are shipped in nitrogen filled plastic containers to help with moisture absorption!
You are correct in that once you expose brake fluids (in general) to atmospheric conditions, they will begin to absorb moisture depending on ambient humidity (great if you live in AZ, bad if you live in FL).
Nice chart:
http://www.proformanceusa.com/castro...rake_fluid.htm
The 'advantage' to SRF is that its wet boiling point (the more practical measure of brake fluid since dry boiling point really only exists in the can or immediately after system installation..yes, brake lines are not 100% airtight) is much higher than say ATE Blue/Gold.
If you open a can and don't use it completely by the end of a driving season (although with occasional bleeds you likely will use it), I would dispose of it (trackside proper disposal or equiv) and start the next season with fresh cans.
SRF is just about as good as it gets, so if you are still having brake pedal problems due to boiling fluid, and not cooking the pads, I don't know your options other than to slow down (or have the Cayenne shed about 1500 lbs or so.....drop the AWD, strip interior....wait for the Clubsport version?).
There is a wealth of information over in the Racing/DE forum if you desire, charts, etc/.
Personally, I love my brakes and really dont mind the cost of SRF!
Most PCA DE regions require that the brake fluid be flushed/changed once per year, in addition, bled prior to each event:
http://www.porschenet.com/DE_PDF_WordFiles/TechForm.pdf (example)
Some brake fluids (Motul 600 IIRC) are shipped in nitrogen filled plastic containers to help with moisture absorption!
You are correct in that once you expose brake fluids (in general) to atmospheric conditions, they will begin to absorb moisture depending on ambient humidity (great if you live in AZ, bad if you live in FL).
Nice chart:
http://www.proformanceusa.com/castro...rake_fluid.htm
The 'advantage' to SRF is that its wet boiling point (the more practical measure of brake fluid since dry boiling point really only exists in the can or immediately after system installation..yes, brake lines are not 100% airtight) is much higher than say ATE Blue/Gold.
If you open a can and don't use it completely by the end of a driving season (although with occasional bleeds you likely will use it), I would dispose of it (trackside proper disposal or equiv) and start the next season with fresh cans.
SRF is just about as good as it gets, so if you are still having brake pedal problems due to boiling fluid, and not cooking the pads, I don't know your options other than to slow down (or have the Cayenne shed about 1500 lbs or so.....drop the AWD, strip interior....wait for the Clubsport version?).
There is a wealth of information over in the Racing/DE forum if you desire, charts, etc/.
Personally, I love my brakes and really dont mind the cost of SRF!
Last edited by ltc; 10-19-2004 at 09:40 PM.
10-19-2004, 11:32 AM
#3
Rennlist Member
Thread Starter
Lewis
Thanks again for sharing your knowledge, you are the man. Im glad you got a cay so you check out this forum, your input helps all of us!
Thanks again
tom 
Thanks again for sharing your knowledge, you are the man. Im glad you got a cay so you check out this forum, your input helps all of us!
Thanks again
tom
10-19-2004, 01:38 PM
#5
Burning Brakes
Lewis is right on the money. The point is, save what you do not use in the initial change over because you WILL probably need it throughout the course of the season. Often the first few laps with a new set of pads will boil the fluid. It is essential then that you have some to bleed out with.
Have you considered finding a way to improve airflow to the brakes? Are there still rock shields on the back side that could be removed to improve airflow? It will likely be a constant battle considering the weight of the Cay.
Have you considered finding a way to improve airflow to the brakes? Are there still rock shields on the back side that could be removed to improve airflow? It will likely be a constant battle considering the weight of the Cay.
Jk, Cool Car...
10-19-2004, 11:33 PM
#7
Nordschleife Master
Originally Posted by ltc
SRF is just about as good as it gets, so if you are still having brake pedal problems due to boiling fluid, and not cooking the pads, I don't know your options other than to slow down (or have the Cayenne shed about 1500 lbs or so.....drop the AWD, strip interior....wait for the Clubsport version?).
1. Try getting some race pads (heck, do they even make race pads forthe Cayenne?)?
2. Try routing some cooling to the fronts (will likely be a custom job, as I doubt anyone makes a kit with backing plates, etc.).
Trending Topics
10-21-2004, 12:24 PM
#8
Rennlist Member
Thread Starter
Brent
Once you open a liter of SRF is it still good to do the bleeding at the track with or does it drop to its wet boiling point??
Alex
not a bad idea! But Im going to hold on to the watch!!! Thanks
Pesky
No brake upgrades for the cayS If anyone hears anything I would love to know, Of to Moroso this weekend, auto cross in two weeks then Sebring!!
Once you open a liter of SRF is it still good to do the bleeding at the track with or does it drop to its wet boiling point??
Alex
not a bad idea! But Im going to hold on to the watch!!! Thanks
Pesky
No brake upgrades for the cayS If anyone hears anything I would love to know, Of to Moroso this weekend, auto cross in two weeks then Sebring!!
