Dumb Question Thread - No Flaming Allowed

[IamFODI]

What's the shelf life of brake fluid? Asking about fluid in a previously opened container but the fluid isn't used, and brand new in a sealed unopened container. If I check the moisture is that a good enough indicator that it's good or not?

Not sure how useful my experience/perspective is, but...

All my brake fluid is SRF (thank-you, FCP Euro), which is is supposedly less hygroscopic than many fluids, and even its wet boiling point is still high enough for street use. So, for the Mazda, I'll use unsealed but unused brake fluid as long as my brake fluid test pen shows no moisture. I know pens are not super trustworthy, but SRF is such hilarious overkill that I figure I'm okay using it as long as the pen reads zero moisture on all its modes.

...But for the M3, I'll still only use fluid from sealed, unopened containers (largely because occasional track time).

[Slideways]

Not sure how useful my experience/perspective is, but...

All my brake fluid is SRF (thank-you, FCP Euro), which is is supposedly less hygroscopic than many fluids, and even its wet boiling point is still high enough for street use. So, for the Mazda, I'll use unsealed but unused brake fluid as long as my brake fluid test pen shows no moisture. I know pens are not super trustworthy, but SRF is such hilarious overkill that I figure I'm okay using it as long as the pen reads zero moisture on all its modes.

...But for the M3, I'll still only use fluid from sealed, unopened containers (largely because occasional track time).

I would guess it depends on the environment where the container is kept. If it is stored in a dry environment with the container in a sealed plastic bag, the brake fluids moisture content should not change much and will probably still test good. Found this video where the owner is testing Motul RBF 600:

[Nate047]

Thanks guys, I have some LiquiMoly fluid left over and I will test it and see.