machina

Found a sealed can in the garage probably 3-4 years old.

Think its OK to use?

Mike Buck

I would use it.

Hopefully Kurt M will chime in with his data involving an open can of ATE and his fluid tester.

Steve Weiner-Rennsport Systems

If the can is unopened, its as good as new (because it is),...

NJcroc

That can is fine and as steve said it is new

Scootin159

I'd be interested in this as well. I always crack open a fresh can when I do a full fluid change at the beginning of the season, but I then reuse the "leftover" the remainder of the season for doing quick bleeds. I've always wondered if it was decremental to use fluid which had been exposed to the open air for a while. I'm sure stuff that was left in an open (and reclosed) can is just as good if not better than the stuff in the car, but what about if I have some left in my power bleeder which is basically open to the air?

Jewels

I would toss the stuff in the power bleeder as it had been under compressed air and possible condamination. In the can ..save it for one racing season to be used before any large change on temperture. This is what I do in the race car and it has worked fine over the last 19 years.

kurt M

Got a 1/2 can that I found a few years ago that was first opened and 1/2 used quite a few years before that. I have a true boil point tester and I test the can from time to time when I remember and have the tester out for something else. So far it has lost 4 deg of max temp. That is less than one deg per year since being opened. I have seen in use fluid loose more than this in a few days in the soggy summers around here.

Also I have found that there is sometimes a differential between the fluid in the reservoir and in the calipers. The calipers often have the least water contaminated fluid. With that in mind partial bleeds would only move the more water contaminated fluid to the calipers where the heat is. Much depends on the car use profile and location. Live in the hot end of AZ? you fluid will time out on other forms of contamination such as seal and caliper wall material before it hits the wet boil point. (wet is 3% water uptake) In this case partial flushes will remove what might be the more contaminated and heat stressed fluid.
Live is soggy hot northern VA? Don't partial flush, full flush and suck out the fluid in the reservoir before flushing.

Just an opinion bases on my own non scientific tests. YMMV.

Send me the can I will test it both with the tester and then in my car and report back.

silver44

I am not casting doubt on this but I have been superstitiously religious about brake fluid (ATE Blue) and open a new can for every race. I was always afraid of it being contaminated and wasn't sure how long that process would take. 19 years is a good long time of testing.

bgiere

I have been using Castrol SRF and bleeding twice a year with 10-12 races/season. I cannot imagine bleeding after every session as some people do unless you are seriously overheating your brakes or braking from very,very high speeds in a heavy car. I believe in safety first but also in intelligent conservation. The unopened can of brake fluid is fine to use. And Kurt M's moisture absorption study mirrors what I have seen testing for moisture in hydraulic systems. I think people get a tad carried away when it comes to fluids, both oil and brake. But do what makes you comfortable so you can race with confidence.

jrgordonsenior

Not to turn this thread, but do yourself a favor and try SRF or Motul. You'll wonder why you spent so much time bleeding your brakes with that Blue stuff...

bgiere

Ditto on getting away from the Blue stuff....It's cheap...but it's really expensive if you know what i mean.

TrackDays247.com

BTW, run the power bleeder (MOTIV) dry - no gooey crap to attract water -

silver44

+1 on doing what makes you feel safe and comfortable...I bleed my brakes once a day on a race weekend...I like that firm pedal feeling.

Gasser

Yes, I have freinds that bleed all the time, constantly fooling around with the fluid. I put Motul in and ran at Hallett around 5 or 6 times and other tracks and never felt the need to bleed the brakes. Always a rock hard brake peddle. I flush once or twice per year unless I have problems. Hallett by the way is pretty hard on brakes.

ltc

+ 1 for Castrol SRF.
Won't consider anything else....well, maybe Motul RBF (what I use in my son's karts) in an emergency.