Brake Fluid Question

[Doc308]

I have a container of Castrol brake fluid which I opened briefly to top off my reservoir about 2 years ago during a fluid change. I immediately put the cap back on and it has sat for this period of time.

Q--Would it be safe to use this for my next fluid change or would having had the cap off for a few minutes 2 years ago compromise the quality of the fluid?

 

[pgilliam1]

First, is it worth the risk? Second, if the fluid has been in a climate controlled environment, then the likelyhood of condensation forming would be minimal. If it has been subjected to climate fluctuations then moisture contamination from condensation would be more likely. It's all a guess, and to me it wouldn't be worth the worry.
Happy Motoring!

 

[EK]

As a reference, I got this response from ATE Tech Support regarding the shelf life of their brake fluid (which comes in metal containers instead of plastic bottles):

All Brake Fluids
With temps between -20 C and 40 C up to 5 years in the initially closed tins.
* once opened, use within 1 year

 

[bobert486]

its probably a piece of mind to simply buy another bottle. BUT, for information purposes I too would like to know how long brake fluid lasts.

According to the statement above, once the bottle is opened(exposed to environment) the shelf life is 1 year. IF that is the case, then how does one explain the fluid thats been in the brake system. Does that mean it can only last 1 year (we all know thats not true). After all, the fluid has been exposed to the air when it was initially poured into the system not to mention opening up the cap every now and then to check fluid levels.

That logic just doesnt make sense.... someone enlighten me.







perhaps Im just over analyzing it

 

[EK]

ATE lists different change intervals (from 1 to 3 years) for different fluid types.

My interpretation is the change interval is independent of whether the fluid is fresh or <1 year old. It seems reasonable to use > 1 year and < 2 year old fluid and reduce the change interval accordingly, but that's a lot of labor to save a few dollars.

It's wise to change with fresh fluid every 2 years, eat your veggie, exercise regularly, ...