merchauser

I have about 1/2 of a one litre tin of ATE 200 on the shelf that I opened Nov. 2018. Understanding the hydroscopic nature of brake fluid and wonder
if I can use this or just discard and start fresh? Not sure if it matters, but I live in a very humid climate and the fluid has been stored in my garage.

FredR

Paul,

I would discard it. Shelf life implies age without opening the tin. Once opened you have no idea how much moisture has been absorbed especially in a humid climate like yours.

StratfordShark

Best throw it away (responsibly!). If it was sealed it would be ok for 5-10 years, but not once open. Cheap enough to buy fresh!

merchauser

^^^^^^got it! thanks for the help. cheap enough to buy new fluid.

for future knowledge, how long (after opening) is it safe to use brake fluid?

GregBBRD

Well, if it is good for 2 years in the vehicle, with open air exchange everytime the brakes get hot and then cool down, it has to be fine on the shelf for at least that period of time, right?

Sitting on the shelf, with the lid sealed, the brake fluid can only absorb the little bit of moisture that was in the original air that displaced the removed fluid.

Unless you last did your brake fluid exchange during the great flood, in Genesis, I'd use it.

Strosek Ultra

Paul, get yourself a LED brake fluid tester.
Åke
https://rxmechanic.com/best-brake-fluid-tester/

Geza

Hygroscopic is the term you were referring to. Personally, I would only consider using it if I needed it to top off a reservoir (not opening another can).

SwayBar

This is exactly what I've thought many times over the years.

However, if I were flushing the brake/clutch lines, I'd certainly use an un-opened can.

davek9

That's what I use, when in doubt, measure it
(the plastic on that unit is really brittle, the probe cap cracked on mine)

Dave K

GregBBRD

We use a tremendous amount of brake fluid, so the opened cans never sit around for more than a week or so (most of the time a shorter period of time than that.). We use opened cans to top off vehicles and to start the flushing process.....figuring that the tiny bit of moisture in the recently opened can is nothing compared to the 15 year old fluid we are flushing out.

We always end up doing the final bit of flushing and bleeding with a new can...the process always takes more fluid than whatever is left in a can, from the previous job.

dr bob

I had to verify that the Great Flood was in Genesis....

enthusiast

The Ate brand does have a shelf life of five years, listed in their technical data sheets and products. Years ago the expiration date was not clearly marked on the container but now it is (see photos front side of can at bottom and backside Paragraph 5).

"This product data sheet describes the properties of the ATE DOT 4 TYP 200 brake fluid intended for use as hydraulic fluids in brake and clutch systems of motor vehicles.

This brake fluid for hydraulic brake and clutch systems of motor vehicles exhibits the best capability for water absorption and the highest boiling point reserve of all ATE brake fluids. The composition is governed by the water-binding polyethylene glycol ether boric acid esters and additives specially developed for this high-performance fluid. The wet boiling point has been maximized at approx. 200°C in order to permit long intervals between brake fluid changes and to minimize the risk of vapor lock caused by used, watered brake fluid in heated-up brake calipers after extremely severe braking. ATE DOT 4 TYP 200 brake fluid meets and even exceeds the requirements of brake fluid standards including FMVSS No. 116 – DOT 4, SAE J1704 and ISO 4925, Class 4.

Shelf life at storage temperatures of –20° C/–4° F to 40° C/104° F: Up to 5 years in the original, factory-sealed packaging.

Product properties:
Condition Homogenous, transparent
Color yellow
Boiling point min. 280° C/536° F
Wet boiling point min. 198° C/388,4° F
Viscosity at –40° C/–40° F max. 1,400 mm²/s
Viscosity at +100° C/212° F 2.2 to 2.8 mm²/s
Water content max. 0.20%

Brake fluid must be replaced regularly. The replacement intervals specified by the vehicle manufacturer must be complied with. The instructions of the vehicle manufacturer with respect to the brake fluid specification must be observed.

A Safety Data Sheet as well as additional information regarding this topic are available under www.ate.de"

.

996AE

You can buy a tester for brake fluid for 10.00

No reason to guess