Shelf life of brake fluid??

[sothpaw]

What is the shelf life of brake fluid?

If you have sealed, (never opened) brake fluid which is several years old, stored in garage and indoors, is it still no good?

--Reason I ask: I had my fluid BOIL, at the track Friday, fortunately at the end of the last run(although I could feel the pedal getting worse during the run).
I had just had it changed by someone else 2-3 wks prior; used high temp. fluid I had purchased(never opened--seal was intact) a few years back.

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[KOPBET]

Was the container plastic?

I believe brake fluid in plastic containers will have a fairly short shelf life even unopened, perhaps a couple of years. But, you don't know how long it was on the merchant's shelf before you bought it unless you can find a product date on the container. Much, much shorter life if opened.

 

[Grizzly]

I use brake fluid so seldom, that I don't buy it until I need it, and then dispose of the opened can. I have heard so many horror stories, that for the little it costs I just buy new every time.

 

[taegdh]

I've heard that the new containers (plastic) aren't as "air tight" as the old metal containers, and hence they would allow moisture to become introduced into the fluid. Too bad there isn't an indicator to let you know when moisture has been absorbed by the fluid, (other than a milky color that you can see when it is in a clear glass container after you've pumped it out)
I've been warned, and heeded the words of my predecessors, only buy what you'll use at that time, and don't let it sit for more than a month if you can help it. Moisture seems to be attracted to it. Like nails to a magnet or a new tire.

 

[sothpaw]

Was the container plastic?

NO, they were metal containers. But they were a couple of years old.

Is the moisture issue as critical with the hydraulic clutch fluid? I just bought the GM stuff (pricy) and only used a little. If I have to throw it away, I will have to use the cheap stuff.

 

[Ken]

Too bad there isn't an indicator to let you know when moisture has been absorbed by the fluid...

Ah, but there is! A company called Acustrip® had a test strip in the works in 2000:

ACUSTRIP® Company, Inc ANNOUNCES A NEW PRODUCT ACU8000 A NEW TEST FOR MEASURING MOISTURE IN DOT3, DOT4 AND SYNTHETIC BRAKE FLUIDS

Mountain Lakes, NJ (Jan 2000) ACUSTRIP® Company, Inc. has announced a new test strip for measuring moisture in brake fluid. This dip n' read test enables the professional service provider, or the DIY'er to quickly test brake fluid for the presence of corrosion causing moisture. As an incremental service a mechanic can demonstrate quickly to a concerned customer the condition of the brake fluid. It has been recommended that this test should be done at least once per year. Today, to do the test, a laboratory or service station must have expensive and delicate equipment. With ACUSTRIP® Brake test mechanics can perform an evaluation of the brake fluid quickly and easily. There is no need for expensive equipment or to send a sample to a laboratory. The brake test kit contains all the necessary materials and instructions to perform 30 tests.

Seeing as how that write-up was done in late 2000, I imagine the product's on the shelves now.

As for the shelf life of a container of brake fluid, brake fluid should be stored in its original container in a clean, dry location at or below room temperature, preferably separated from similar storage of petroleum products or fluid materials used for maintenance purposes, thereby lessening the chance of contamination. Always use the original containers, which should be tightly sealed to avoid water absorption and be clearly marked.

Under normal conditions of storage, new, unopened containers of brake fluid, with their foil seal intact, will have a shelf life of two years.

 

[c4cruiser]

Unless you are using expensive race grade fluids like Motul or such, the cost of fluid is really cheap for thelevel of safety it provides us. I buy the small cans of fluid for a flush job. A C4 system should take about a quart for a full flush so that size works too but I don't usually keep any unused fluid from a large bottle like that.

I bleed my brakes before and after eack track day so I can go through a fair amount of fluid during the year. I buy what I need for a bleeding operation and keep a spare bottle with the equipment I take with me to the track and then rotate that bottle at the next fluid bleed.