How to safely store your brake fluid for a while?

[e9999]

as we all know, brake fluid is hygroscopic and will pick up water after a while if left in a open container. Water in the fluid is bad as it makes it possible for the fluid to boil more readily if the brake system becomes very hot. Not good. So I've been careful about that and of course have some long ago-opened brake fluid on the shelves. This can't be used for braking systems but not all is lost since it can be used for paint removal. But anyway it is a waste.

So I was wondering if it would be OK to use propane to "protect" the fluid, as one might do for paint for example. It's not obvious, I guess, first because the point is not the oxygen as for paint, it's water, so the water vapor may still infiltrate the propane maybe. I'm no chemist so I'm also wondering if there may be some detrimental reaction between the propane and the fluid.

A long shot maybe, and only a few bucks so not that big a deal, but curious so thought I'd ask in case somebody knows. Maybe would help enough that I'd feel good about using the fluid a few days after opening rather than -paranoically- abandoning it the day after the bottle is opened.

Thoughts?

 

[PAToyota]

My feeling is that opening the container is about the same as opening the reservoir in the vehicle. If opening the container "instantly" contaminates it, you're already screwed in the operation of opening the reservoir, pouring the fluid from the container into the reservoir, and closing everything back up.

So my position is to change the fluid every couple years - both what is in the system as well as on the shelf. I mark the date on the container when I open it and keep track of when it is changed in the vehicle.

 

[Cuerno Largo]

I guess one could rig up some sort of vacuum device..... or replace the air that would fill the area of the container previously displaced by the fluid with a noble gas.

Personally, I buy the small bottles and only keep enough on hand for my immediate needs, plus one small bottle that remains unopened for "just in case."

 

[e9999]

My feeling is that opening the container is about the same as opening the reservoir in the vehicle. If opening the container "instantly" contaminates it, you're already screwed in the operation of opening the reservoir, pouring the fluid from the container into the reservoir, and closing everything back up.

So my position is to change the fluid every couple years - both what is in the system as well as on the shelf. I mark the date on the container when I open it and keep track of when it is changed in the vehicle.

are you saying that you are using 1+ year old open bottles of brake fluid to put in your system?

what I've done in the past is to put a piece of plastic film on the threaded spout and the cap on top of that in the hope that it would reduce or zero water contamination after the initial pour, but who knows, so I still don't use it after the first pour...

 

[tag3]

How long has the fluid been in the reservoir on the truck?

 

[PAToyota]

are you saying that you are using 1+ year old open bottles of brake fluid to put in your system?

How long has the fluid been in the reservoir on the truck?

Exactly. If the stuff that is in the truck has been "open" for a year, what is the difference from a bottle on the shelf that has been open for a year?

That said, if I'm flushing and filling what is in the truck I only use a brand new unopened bottle. If an open bottle has sat on the shelf for a year and a half, I'm not going to put it in the truck where it will be for another two years.

 

[e9999]

Exactly. If the stuff that is in the truck has been "open" for a year, what is the difference from a bottle on the shelf that has been open for a year?snip

.

well, I think there may well be a difference in the quality of the sealing between a 5c brake can and the brake fluid reservoir on our trucks.. Remember that the typical brake can does come with a seal under the cap.

 

[LandCruiserPhil]

I would be careful mixing anything with brake fluid
I carry chlorine for use to purify water and mixed with brake fluid it becomes a slightly violent but effect chemical fire starter.

EDIT - READ
Mixing brake fluid & chlorine is a survival technique!
If you try this and get hurt dont blame me

 

[PAToyota]

well, I think there may well be a difference in the quality of the sealing between a 5c brake can and the brake fluid reservoir on our trucks.. Remember that the typical brake can does come with a seal under the cap.

Take a look at them. The only reason for the seal is to guarantee that it reaches you in a sealed state. I remember when brake fluid came in a metal can with a screwtop lid - and when aspirin and everything else you buy didn't come with triple safety seals either.

 

[45Kevin]

How much water is in the 3 cubic inches of air that gets into an opened bottle of brake fluid?

Is it really enough to make a difference?

 

[e9999]

How much water is in the 3 cubic inches of air that gets into an opened bottle of brake fluid?

Is it really enough to make a difference?

well, if it does not make a difference, then we should probably not bother changing the fluid in the brake system ever to avoid boiling problems, I guess, since it likely would not absorb water there either. Yet, it seems that it is recommended to change the fluid every couple of years and I also do remember reading in various places never to use fluid from an open container when filling the system.
Of course, I'm no expert on this, so, lacking a definitive answer about how old is too old, or a clever way to preserve the fluid, I guess I'll just stick with using new bottles each time and letting the old stuff accumulate in the garage.

 

[PAToyota]

You're sort of going from one extreme to the other. Brake fluid absorbs water over time - given the chance. Change the fluid in the truck every two years or so - as they recommend. If you need to top off, you can use the fluid in the re-sealed container that's in the garage. If you're flushing the system, buy a fresh bottle.

 

[itbrokeagain]

I open a bottle use what I need and put it on the shelf. When I need it again at a later time I get that bottle back out use what I need and put it back on the shelf. No problems yet

 

[KLF]

^^^ Agreed.

I really think you guys are making a big deal out of nothing. The amount of water that *might* get into an opened bottle of fluid is insignificant. Besides, when brake fluid gets contaminated with water, it turns brown.

 

[neoworm]

^^^ Agreed.

I really think you guys are making a big deal out of nothing. The amount of water that *might* get into an opened bottle of fluid is insignificant. Besides, when brake fluid gets contaminated with water, it turns brown.

No kidding, this debate is ridiculous.

 

[3DAMAN!]

No kidding, this debate is ridiculous.

X2
Use it as needed, seal the cap and shelf it until next time

 

[e9999]

OK, OK, I will use the old stuff then. I will probably crash. If I do die I will come back for a visit as the angel of headgasket death. Consider yourselves warned...

 

[scottm]

How do you dispose of used or unused brake fluid? The guy I take my used oil to burns the oil for heat, can't have contaminates in it. He says he talked to the local municipal sewage treatment folks, and was told it can go through their plant no problem. From the University of Wisconsin:

Brake Fluid Flush small quantities down home drain if connected to a metropolitan sewer system. Dilute.

Brake fluid is chemically similar to antifreeze. Flush small quantities-less than one gallon at a time-down an indoor drain and dilute with water. If you have a septic system, check the antifreeze advice for appropriate disposal.

From Popular Mechanics:

BRAKE FLUID
Brake fluid is alcohol-based. It's toxic when ingested. When bleeding brakes, catch the runoff in a jar. Brake fluid from a jar that's been opened for more than a few months probably has absorbed enough water to reduce its boiling point past the point of safety. To dispose of new or unused brake fluid, pour it into a container of cat litter. The brake fluid will evaporate within a few days. As with paint, keep this away from pets and children, and any source of ignition.

 

[KLF]

Good question. In the past I've put it in my waste oil, but I don't think I'll do that anymore. I guess I like the kitty litter idea the best, although it WILL NOT evaporate. Try it, the stuff stays around forever, just like anti-freeze. No way I'm pouring that stuff into my septic system. Getting rid of a couple gallons of anti=freeze is a huge PITA around here, last time I convinced a mechanic friend to take it with him, he snuck it into the disposal tank at work while the boss wasn't looking.

"Brake fluid from a jar that's been opened for more than a few months probably has absorbed enough water to reduce its boiling point past the point of safety."

The only way this is true would be if you left the cap off.

 

[WarDamnEagle]

"Brake fluid from a jar that's been opened for more than a few months probably has absorbed enough water to reduce its boiling point past the point of safety."

The only way this is true would be if you left the cap off.

That was in the context of "when bleeding brakes, catch the runoff in a jar". In other words, it's already used fluid but I agree in general that if you put the cap back on that you aren't going to have a problem.