Hot DE, brake fluid question....

[Scott in Houston]

I just finished a Texas, August DE. HOT!

Anyway, on the very last run session, I got a brake fluid warning light which isn't too uncommon out there w/ our cars b/c the high lateral Gs can cause the sensors to misread the level, but I pulled in to make sure (for obvious reasons).

Backing up a bit, the dealer bled and changed my brake fluid the week before. At one time in the weekend, I noticed the fluid level was above the "Max" marker in the reservoir, but I figured that was because I had been running, and it was just hot.

Now back to my story, when the sensor light came on, I pulled in to check it out. I turned off the car and restarted it. The light was gone, so I figured it was ok. Then, I pulled into a garage to make sure. I looked at the reservoir, and there was a small amount of brake fluid on the outside of the reservoir. Basically, there's a rim around the top of the reservoir, that looks like it's there for just that purpose, catching excess fluid.

I have never seen that. The guy next to me told me that it probably boiled and that it is normal for some to come out when it does.

This did not make me happy. Is this truly "OK"? I don't think much came out, and I don't think any ran over and down into my trunk area (should I be more concerned about that?).

What should be my next step?

1) take it to dealer who bled and replaced fluid on my last service?

2) not worry about it and chalk it up to a hot hot day at the track

3) other

Number 1 bothers me, because I worry that they may 'cover up' any mistake they made that caused it such as over filling or whatever.

I really know nothing about this topic, so any help is appreciated!

Scott in Houston

[Tool Pants]

There is a vent in the cap which you cannot see unless you take a cap apart. Fluid went out the vent for whatever reason and went the only place it could go, on top of the reservoir. Some cars have a vent tube for this reason, just like the vent tube on your battery.

If it is not too late you can remove the plastic cover to see if any fluid got on the paint, but if it did it is paint you can't see anyway. Jeff

[Palting 996 C4S]

You did lose some fluid through the vent.

The "boiled" theory is nonsense. You would have noted a definite fade in the brakes, and there would be a spongy feel now.

By the third run during autocross, when I'm really cooking, my brake level light does go on pretty regularly. The G's probably do make the fluid climb up the sides of the reservoir, enough to make the sensor think it's running low. I've not seen any fluid outside the reservoir. I've only had it go on once during DE, though. Boy, you must really be cooking those corners!!!

I posted a simillar thread in the past, and had some responses suggest to bleed the brakes. Might not be a bad idea, but I did that, and still had the light go on at the next autocross. So long as the brakes feel fine, and your level is fine, I wouldn't do anything since everything is probably OK, IMHO.

[dj996]

Scott, that is a little weird since you just had the system bled. Most likely nothing to worry about, you were running pretty hard on a really hot day. If it's overfilled, you could carefully remove a small amount of the fluid with something like an old turkey baster. But be real careful, brake fluid can take the paint off. Also if you suspect boiling make sure the dealer used the same spec brake fluid in terms the proper boiling point. I believe factory fill is the ATE super blue racing or gold (color is the only difference).