jonecap

I took my C4 to VIR in December '08 for a HPDE and changed the brakes and brake fluid before I went. I put Valvoline Synthetic DOT 4 fluid in. I do not remember which pads I used, but they were/are good pads. The brakes performed well at the event. I could smell them a few times, but no fade.

Since that time I've probably driven the car 1,500 miles. I'm taking the same car back to VIR this weekend for another HPDE ( on street tires).

Is it really necessary to change the fluid again or am I wasting my time and energy?

AU N EGL

Change brake fluid before and after each track weekend.

at a min before each track weekend.

mgarfias

Well, if you're not getting it hot, then I see no reason to change. If you're not experiencing fade/long pedal and you have stock brakes you're not pushing the car very hard, and that makes me question the need to change.

If it was me? I'd flush it, but I've experienced boiling fluid in the past. I do not want to experience that ever again.

RaleighSS

Fluid is cheep change it your yours and others safety is not worth the 10 bucks ya save.... the only way to know it should have been changed is when its too late ....

jonecap

Good feedback guys...I'll get it changed. Thanks.

Greywolfe

While your doing that check out the pads for thickness and the rotors for cracks. When you throw the wheel back on try to rock it from top to bottom to check for wheel bearing wear.

I also change my oil before each track weekend so I know I've got nice fresh oil in there (engine).

rfn026

Here's more than you need to know about brake fluid.

Richard Newton
Speed TV Blog

AU N EGL

Brake fluid is hygroscopic, or it absorbers water. hence the DRY and WET boiling points. Stopping or hard braking is more effective when the brake fluid is closes to its DRY boiling point. and weakest near its WET boiling point.

Brake fluid at its WET boiling point is also considered to be 'saturated" or up to 4% water, with in 30 days of opening a bottle.

so when the brake fluid is used in a car or race / track car that brake fluid when put in right before the event from a NEW bottle, will be saturated with water, go from the DRY boiling point to the WET boiling point by the end of your two day event.

When you look at the DRY to WET temps that is quite a bit of a difference.

Plus taking the time to change / flush your brake fluid gives you time to check your brake pads, check each bolt in each wheel well. ir go over your tech sheet for each event.


BRAKE FLUID COMPARISON CHART
Brand Wet Boiling Point Dry Boiling Point
Castrol SRF 518°F 590°F
Motul RBF600 420°F 593°F
Wilwood EXP 600 417°F 626°F
AP-600 410°F 572°F
Brembo LCF 600 399°F 600°F
ATE-Super Blue 392°F 536°F
Valvoline 333°F 513°F
Castrol LMA 311°F 446°F
Ford HD 290°F 550°F
Wilwood 570 284°F 570°F
PFC-Z rated 284°F 550°F
AP-550 284°F 550°F

jaa1992

Before I changed booster/master/calipers I was bleeding after every day and almost a full flush after every event. Always got grey fluid out of it.

Now I can bleed (2 - 3 pumps) after each event. Still haven't decided on a flush after 4 or 6 weekends.
December 08 thats almost 18 months!
Flush it completely with fresh fluid!

John Shiels

We should take a bottle of SRF and take a sample and test it for moisture. Then leave cap off 1 week, 2 weeks, 1 month 2 months, 3 months, 4 months and 6 months. probably cost bit over 200 bucks for the tests.

Wayne O

Good advice!

ZR1 MK

With 1500 miles, you want to change all fluid, but if the events and miles are small and close together, you can get away without doing the rears.

jonecap

Just got done changing the brake fluid and can't get over how much better the brakes feel now. As soon as I opened the bleeder valve on the driver's side front tire, a bunch of bubbles came out. Apparently I had a lot of air in the lines from the last time they were bled. Much better now!

Before the brakes were bled tonight, I could not get the brakes to lock at all and kick the ABS on. Now I can lock the front tires and engage the ABS fairly easy which tells me they are working much better. Still not as good as the brakes on my daily driver '02 BMW 330i

Pads looked great and so do the rotors. I think I'm ready to tackle VIR now.

c4cruiser

Doing a brake fluid flush is a fairly simple chore to do especially if you have Speed Bleeders on each caliper or use a pressure bleeder like the Motive Bleeder. Either method is a one person operation.

For example, I can do a complete flush of the fluid on my 87 in just about 30-45 minutes depending on the beer breaks . That included raising the car, pulling the wheels, open the can of fluid and bleed each caliper, then re-installing the wheels and taking it off the jack stands.

I use ATE Super Blue and TYP200 fluids (DOT4) alternatively when flushing. The Super Blue has a blue tint and the TYP200 is gold. Both fluids are exactly the same except for color. It's easy to tell when one fluid is gone as the color changes.

My 87 takes about 3 pints to do a full flush. The balance of the fluid gets used when I do a quick bleed of each caliper before and after a track day. That only takes about 1/2 pint.

I don't do anything with the ABS as the only time fluid moves thru it is when the unit is activated in braking or on startup and the system does a self-test. Otherwise you need a scan tool that has the ability to run the ABS pump to push fluid through the system.

Bill Dearborn

For the 17 seasons I have been doing track events I have changed the fluid just before the first event of the season and then doing bleeds before each event if they come close together. If there is more than a month between events then I do another flush just before the next event. I don't bleed at the events and I don't bleed after the event. I used to use the Ford Super Duty DOT 3 Fuid but Ford lowered the dry boiling point to 500 degrees so now I use Wilwood 570 DOT 3 Fluid I have never boiled either of those brake fluids even when using brake pads that can run as high as 1300 degrees.

Bill

JimbeauZ06

Valvoline Synthetic DOT 4 is not a good choice for track use IMO. I would highly suggest moving to a higher quality fluid like Super Blue, Motul etc.

I started with Valvoline and there is definitley a noticeable difference in pedal feel and brake fade. Even with the good stuff you should change at minimum every 90 days and ideally after each track event as already mentioned.

RaleighSS

ATE super blue / clear an be found at about 14$ . The can will flush system completely 2 times. (but have to worry about shelf life if not used quickly after opening)

I buy 1 can ... flush brakes and clutch once before track event then take remainder to track. Any left over after event gets put into my Wife's BMW on next oil change (just daily drive)

0Anthony @ LGMotorsports

I'd like to do that as well. Heck I could probably take a bottle that came out of the car just to see what it does after a weekend in the brake system.

SRF is some mean stuff.....nothing else goes in the cars but that.

You also have to think about the total cap. of the car and the calipers as well. A stock Corvette caliper has very little heat protection nor does it carry very much fluid, I would probably bleed the brakes once a day at the track myself. Now something like the ALMS car with the HUGE Alcon's it has and the big reservoirs we may not touch it all weekend and just do a quick bleed before the race to get fresh fluid in the calipers.

Either way normal brake maintenance is should be considered priority #1

John Shiels

Everything else is a joke compared to SRF. Years ago Lou would preach to me so I bit the bullet. Never looked back, never had a problem. I even went 999 track only miles without a problem. It was at least 4-5 days and a weeks apart. That was more than one set of Wilwood pads in the SL6 with NO bleed. I just did it to see what would happen. Considering I get the rotors red in daylight pictures they were hot! If you can't stop nothing else matters!

ZR1 MK

Ive never tried SRF.
So the fluid will withsand the punishment regarding fluid boiling, but what about pedal feel after having the same fluid in for so long?