Brake Fluid

Is it ok to use brake fluid that is in a sealed container ( never opened) that is 7 to 8 years old?.

I certainly wouldn’t but you always get it tested if you have a lot of it.

I would say it’s okay, because it was sealed tight. Brake fluid is hygroscopic and takes on water. How’s it going to do that if the container has been sealed tight as a drum with the plastic film all these years?

It could be fine, but for $5 a qt of brake fluid, I would not waste my time esp if this is for a flush, just buy a new one.

+1 to what @db4690 said. There might be a very small amount of diffusion through the container if it is plastic, but not enough to be a problem.

@bigbass just to be clear . . .

When you unscrew the cap, if the plastic/metal film is still in place, stretched tight and undamaged, you’ll more than likely be fine.

It’s cheap enough is it worth the gamble? It’s not only your life but others as well.

I must have missed something, @cats. Was the OP asking about smoking a cigarette while filling his gas tank at the stop and shop while the tanker was dumping into the under ground tanks with fuel puddled on the ground? Let me look back over that post. Surely I missed something.

I think it should be ok if never opened. I’m on the cheapo side though. I guess what I’d do is pour 1/2 cup into a clear container and carefully look for any sediment. If nothing visible is floating around and the fluid is transparent and homogeneous looking, me, I’d go ahead and use it. If anything is floating around or the fluid has any sort of a milky or cloudy appearance, I’d toss it.

I would be more concerned that it was the right brake fluid. But, if it’s sealed, it shouldn’t matter if checked like @George says. Otherwise if it won’t break you financially, I would buy some new stuff if you’re refilling, use what you have if it’s compatable and you 're just topping off.

@Rod Knox
Ah, sarcasm. Apparently you must have missed it. No the OP did not post a question as you decribed. That would be an obvious safety risk with no need to post.
My point was even though the container was sealed the product is not that expensive. There is the possibility that even in the small air space in the top of the container could have produced condensation (water) over several years since the storage environment is unknown. Also, we do not know the intentions of the OP (top off m/cyl, flush and fill, fill and leave in). In addition we do not know what the terrain the OP will be driving in. Mountainous terrain does heat the fluid and can even cause it to boil. If there would be a failure caused by the fluid it would effect the OP, passengers and people outside the vehicle. This is unlikely but still a possibility.

With that said, if the OP bought a new container he/she would be out a few bucks. A few bucks is nothing.

There are plenty of 8 year old cars driving around with the original fill of brake fluid in their master cylinders without any major problems…I suspect new fluid from a sealed container would be fine…

Exactly. Try 10 plus years…

I have a particular aversion to “the sky is falling” warnings, @catz. DOT 3 is quite cheap. But if kept tightly sealed it should remain bright and clear and usable for quite a while.

And what do you do with a bottle of old brake fluid? I’d rather use it if sealed tightly instead of recycling it immediately.