NickT

I have some DOT 4 racing brake fluid that I bought some years ago (maybe 6) .. Super Blue.

Never opened and always sealed inside a zip lock bag.

Still safe to use or to be on the safe side should I just get fresh fluid?

Speedtoys

Should be fine in the original container, never cracked open.

Once open..almost impossible to seal it up correctly, or good enough to prevent water from creeping in.


Id say yer good.

GlenL

I'd use it.

NickT

Thanks.. Think I will give it a shot

Speedtoys

No, don't give it a shot! Don't shoot anything!

-Grosse Pointe Blank

NickT

I'd probably miss anyways . . .

BoostBuggy

The general shelf life for DOT 3 or DOT 4 brake fluid is 24 months, even in a sealed, never open container. Brake fluid breaks down over time and as it breaks down it goes acidic. As the ATE fluid typically starts out with a pH that doesn't meet the minimum of 7.0 (neutral pH) it was already slightly acidic when you purchased it. Over time I have no doubt the pH has dropped further.

I don't know about you but I wouldn't be too excited about putting an acidic fluid into my brake system with all those nice metal components for it to attack.

The fact is your entire brake system was designed to perform optimally with some basic expectations in mind, one being that the fluid in the system meet at least the minimum DOT standards. Using a brake fluid that does NOT meet the standards means that you have compromised the operation of the system.

Personally I would discard the ATE and purchase new. Why risk your brake system and very possibly much more for the price of a bottle/can of brake fluid?

123quattro

While what boostbuggy is saying is partially true, I wouldn't worry about running 2 year old sealed brake fluid. Had the can been opened it would be a different story. Plenty of cars are running around with fluid much older than 2 years and they are fine.

dr bob

Turns out that brake fluid itself is really cheap in the giant car cost matrix. If there's any question, pop the bucks for new fluid. Why worry or risk it?

davek9

Just wondering why the fluid could not be tested before using it, like they do at a tech inspection or is that just for moisture?

BoostBuggy

@123quattro You submit that what I have to stated is only "partially true." What is it that I have said that is untrue?

123quattro

It's true in that it's not as good as new fluid. However, what's to say the can you buy at the parts store hasn't been sitting on the shelf for two years? Brake fluid doesn't break down so fast that unopened after 2 years it's no good. It's just not as good as brand new. Even 10 year old used fluid isn't that caustic. It just has a lower boiling point. Most cars on the road have never had their fluid changed and the brake systems are still intact.

hacker-pschorr

Keep in mind the guy behind you hasn't changed his brake fluid in 10+ years and his vehicle weighs 6,500lbs with smaller calipers.

NickT

While I agree that was the cost of brake fluid vs the damage it can cause, I will get new but it's still an interesting topic...

Found this:
https://rennlist.com/forums/racing-a...helf-life.html

It's really split on this from what I have read on the web. A general thread is if the container is metal, then it's probably OK, plastic is definitely out of the question and throw it away.

BoostBuggy

Again, contrary to the conventional wisdom, the material of the container really doesn't make any difference. This isn't to suggest that the HDPE used for the most common plastic container isn't porous, it is. But what is really more important than the container material is the simple fact that brake fluid breaks down over time. This break down is buffered to a degree by the additive package that all brake fluids have (which bring up the topic of the quality of the additive package, but that is another topic) As the brake fluid breaks down it goes acidic. So even in the event the brake fluid is packaged in a metal container, it still is breaking down and there is simply no manner in which to prevent or stop that process.

In the brake fluid industry (in conversations that you will never hear) the standard is 24 months for a shelf life in a unopened, sealed container. And I can think of a major brake fluid manufacturer that will not warranty the performance of their product past 24 months regardless of the material of the container.

I can't state with certainty of it at the moment (I don't have a bottle sitting around to reference) but Castrol SRF used to say on the back label its shelf life was 18 months.