I bought some ATE Super Blue brake fluid a few years ago. I used about an ounce to top off and have not used it since. In total, it was open and exposed to air for about 30 seconds. Is it still good or should I toss it?

Thanks!
Konrad

Toss it.

If it was a sealed container, it would have been ok to use.

Yep toss it. It has sucked up a lot of water by now.

Wait, dont be quick to throw that fluid away.

could still be good, The color of the fluid can indicate how much water is absorbed, the darker it gets, the more water is absorbed in the fluid. if capped tight, and stored in a dry place with minimum temp swings, it could still be fine to use. Go ahead and see if it still has a clearish faint yellow tint, if it looks about the same as new fluid, your good to go.

No cents throwing away good stuff.

if you find the fluid slightly dark, not perfect, it can still be used as a first flush of a dirtier brake system when you do a full flushing of the brakes. You would follow this first flush with a second flush with fresh fluid. I use up to 2 quarts on a 914 to fully flush all four brakes, going around twice, the first time around i use up the partial clean bottle(s) of fluid I have laying around, great money saving trick.

I agree, I would not jeopardize mine, nor my passengers lives over a bottle of old brake fluid. Whats a life worth?

So how anal are you? It's probably fine. Brake fluid itself doesn't go bad for years, as 90 percent of the cars on the road that have never had fluid changed will testify, and 30 seconds with the cap off isn't enough to ruin it either. You introduce more moisture than that to the fluid already in the system when you top it off, and then it will pick up more from moisture with normal use. I guarantee that the bulk dispensers in your local shop all have more exposure than that without problems. Don't be stupid and leave the cap off for hours, of course, but 30 seconds is not going to be a problem and certainly not dangerous. But if you're really anal dump it.

My DDs (Acura & Mazda) recommend brake fluid changes every three years in systems that have vented reservoirs. Fluid manufacturers make this recommendation. Along similar lines, oil manufacturers recommend oil changes every 3,000 miles while engine manufacturers typically double that.

I thought about that little more after posting. What I'm saying is for a street car, because it's pretty difficult to boil brake fluid on the street. But if you track the car you definitely want to be more anal, because you will be cooking things. Sorry, my bad, need to clarify that.

I think even those manufacturer's recommendations tend to be worst case. The fluid guys would recommend that you change it daily if they thought they could get away with it.

Two years is the recommended service interval for Porsche brakes, but the system isn't sealed and brake fluid is hygroscopic which means it attracts H20.

I tend to err on the side of caution, but if it's been in a tightly sealed container inside, I'd use it on my car.

High quality H2O.

Water sucks. It really really sucks...

C'mon it's a Porsche, only the best!

Although I am a firm believer in not going with the " Rinse and REPEAT" suggestions from manufacturers, I would not even use it for flushing a system. Why use a fluid that is known for absorbing moisture and purposely introducing it into any cars brake system, track or street? A quart/litre is not that expensive. Don't forget, you don't know how long it was sitting on the vendors shelf before you picked it up. In the end, it's your car/life, your choice.

I wouldn't have any problem using it in a street car. The factory container, even without the hermetic seal, is an effective barrier against moisture. Not only that, the wet boiling point is quite high.
There's two ways to boil the brakes on the road: forget to release the parking brake before going for a drive, and ignore a sticking caliper.

I always date my racing brake fluid containers the day they're opened.
If I don't use it up in a season on track, it gets used in a street car.
When I was competing in Nationals, I bled the brakes in the race car at least once per race weekend, whether I thought it was needed or not.

Brake fluid experts no longer recommend the "color" test, as it's pretty much been disproven. I wouldn't hesitate to use fluid opened and stored as yours was.

The Cap'n

The color change, as I've been told, is from the breakdown of rubber components in the brake system as well as numerous heat cycles. Color is no indication of age or water contamination. As long as the fluid is sealed correctly during storage I see no reason why you shouldn't use it. I would on the other hand not use fluid thats been sitting for more than five years.

If it was sealed it would keep for years. If it's been opened but still clear it's probably good. But why chance it? For the cost of new fluid, use this stuff to flush/bleed out the old stuff and buy new stuff for your final fill. It will probably be in there for another 20-30 years.
What kind of a price tag would you put on some stupid like brakes, your car or your life?
Just my thought.

.....The fluid in that bottle, is probably purer than the fluid in most of our existing
brake lines!

Double trouble