DAR951

Just "discovered" almost a half a case of unopened ATE brake fluid I'd forgotten I had... Must be at least 1-2 years old (I don't see any MFR dates and don't remember when I bought it). Anybody have an idea of the shelf life of factory sealed brake fluid???

Professor Helmüt Tester

It's brake fluid, not sushi or bread. If it's not opened, it's fine.

TD in DC

Don,

Kurt M did a little experiment where he checked the shelf life of opened brake fluid. He found that it really didn't degrade when it just sat on the shelf provided that the cap was screwed back on tightly, even over a long period of time. So . . . if they are unopened, I am sure you are probably fine.

TD

spazegun2213

agreed

Alan C.

I was recently told by a Motul rep that 12 months was a good rule of thumb. BTW, Motul purges the air gap on top of the fluid witn N2 prior to sealing.

For myself if I have brake fluid that I have had for more than 12 months I pitch it. Why would I keep brake fluid longer than beer

Bull

I'm sure the guy means well, and may be right.....but, I would have to hear it and see proof from someone other than the guy who will sell you your next bottle! Never have seen the proof, nor had a problem with UNOPENED containers.

tkerrmd

I thought that once opened moisture was able to "seep" in and the boiling point moved away from the dry boiling point to the wet boiling point?
Do you guys use brake fluid after it has been opened and on the shelf even for a week?

hacker-pschorr

Any brake fluid I open is tossed out once the cars go into winter storage. It's cheap and I do not usually have a lot left over so why even chance it?

Unopened? You have no idea how long it's been on the shelf before you bought it.

TD in DC

Yes. As I pointed out, Kurt tested the boiling points of an opened (but resealed) can and found that it didn't degrade significantly. Now, I usually do not end up keeping opened cans for more than 2-3 months, but I haven't noticed any problems whatsoever.

I use SRF for the 996 and ATE Blue for the 944 . . .

bgiere

I have been told that brake fluid in plastic containers is more suseptible to moisture creeping in than metal canned brake fluid...Plastic cans of brake fluid should be considered suspect if they are older than 12 months FWIW...Ate comes in metal cans i believe....

Alan C.

I've got a $12.00 can of brake fluid on the shelf and a $50k-$60k car under my butt. When I open the can/bottle I date it. If it isn't gone in 2-4 weeks I toss it. For the small price it doesn't seem worthwhile.

However, SRF is most likely a different story. I'm very tempted to try it next year.

skeetshooter

The type of brake fluid we use in our cars is highly hygroscopic. Plastic containers with plastic caps do allow more moisture to be absorbed than metal containers with metal or plastic caps.

Castrol SRF is the best brake fluid I have ever used. It is also the most expensive I have ever used. My experience with Castrol SRF, Motul 600, and Ate Super Blue came from my motorcycle road racing days. Motul 600 is the second best I used and was better than Ate Super Blue. I did not like the fact that the Motul brake fluid came in a plastic bottle.

I used to completely replace the brake fluid for every race weekend which meant the fluid spent at most one month in the system. I suspect with the capacity of the Porsche systems, you don't change out the brake fluid that often, do you?

I never kept an open bottle of Motul 600 around more than 2 months. Open Ate Super Blue cans were kept up to 4 months. I would keep open Castrol SRF cans around for at least 6 months. Unopened bottles of Motul 600 would be replaced after 6 months. I would keep unopened Castrol SRF and Ate Super Blue cans around at least a year.

The wet boiling point of Castrol SRF is so friggin' high that I don't see a problem keeping unopened cans around longer. But I would not buy it in enough quantity to require that.

Skeeter

10 GT3

I have noticed that brakes fluid in opened containers that sits over time will change color and become darker (like old brake fluid). This is probably due to moisture contamination. I don't worry about the shelf life of my fluid, mostly because I don't let any of my cars go without getting a flush once a year. Any car I track will be flushed every 6 months or less. Basically, I never have a bottle that doesn't get used in a year.

Matt Marks

Don - I would assume it's good for lack of any other information...however based on people's concerns regarding shelf life of open fluid. It seems to me that the seal on fluid reservoir is not any better than the seal on the plastic lid of an open can of ATF - yet we all let the fluid stay in the car for months. Interesting paradox.

FWIW, I change my fluid every 2-3 events as part of normal bleeding.

Matt Marks

BTW, if you're going to toss it - I'll take a can. I'm broke ;-)