silly brake fluid question

[K7GLE]

All -

It always kind of chaps me that I buy a pint of brake fluid, use about 1/10 of it, then have to throw the remainder away because of the "use only brake fluid from an unopened container" commandment.

My understanding of the reason for this is that brake fluid will absorb water vapor from the air, which will potentially boil, or corrode the fittings, or cause some other bad mojo at an inopportune time.

But if a guy kept the once-opened but tightly-sealed container in the freezer, wouldn't that prevent water vapor from entering (since it would all be in solid rather than vapor form)?

Just sayin'

 

[pglaves]

All -

It always kind of chaps me that I buy a pint of brake fluid, use about 1/10 of it, then have to throw the remainder away because of the "use only brake fluid from an unopened container" commandment.

My understanding of the reason for this is that brake fluid will absorb water vapor from the air, which will potentially boil, or corrode the fittings, or cause some other bad mojo at an inopportune time.

But if a guy kept the once-opened but tightly-sealed container in the freezer, wouldn't that prevent water vapor from entering (since it would all be in solid rather than vapor form)?

Just sayin'

Maybe, but brake fluid is cheap and comes in bottles smaller than a pint.

 

[dbrick]

Let's go all out here:

If brake fluid in a new, sealed container doesn't absorb moisture, why can't the user reseal the container? Torquing down the plastic cap ought to seal the container well - one can shake a re-sealed container with no leakage, or submerge an empty container in a bucket of water and squeeze it - no bubbles in the water.

Why isn't this satisfactory to preserve unused brake fluid?

 

[dieselyoda]

Maybe, but brake fluid is cheap and comes in bottles smaller than a pint.

It's just a few bucks. Why gamble?

If you choose to gamble, hedge your bet with a Brake Fluid Tester that test moisture content. Maybe the $$$.$$ you spend on the tester will save you $.

 

[mlytle]

As soon as you break the seal on a new can of fluid, it is exposed to moisture laden air. Sure you can put the cap back on, which limits further moisture, but the absorbent process had begun.

That said, I do keep using from an opened can, but only for a month or so. And I change brake fluid every few months. It is cheap insurance.

 

[cycleman2]

Think about it. Once you open the container air enters and occupies the space. In most cases you are going to bleed the brakes/clutch ( every year or at the longest every 2 yrs ), you fill the master cylinders and then that part full container is going to sit for the remainder of the year or 2 years before you will use it again. If you buy the pint or 500 ml container it will do all the brakes and the clutch, with just a bit left over, very little waste.

So why take the chance. Use what you need and throw the rest away.

 

[BMARC153920]

And the cap isn't the seal that foil you remove is really the seal.

 

[AntonLargiader]

Shops buy brake fluid by the gallon. Do any of you really think they crack open a fresh gallon for each bike they service?

 

[henzilla]

own more bikes

We use it often, doesn't sit long.

 

[gsaddict]

Shops buy brake fluid by the gallon. Do any of you really think they crack open a fresh gallon for each bike they service?

 

[dieselyoda]

Shops buy brake fluid by the gallon. Do any of you really think they crack open a fresh gallon for each bike they service?

Fair and accurate comment. That's why we use a brake fluid tester on every jug before it goes in. Stopping a bike with two on it and the brakes fail generally is bad for just two. Try stopping 15,000 lbs of loader and see what happens when the brakes fail. The math is never very positive when the machine eventually comes to a stop.

 

[69zeff65]

A positive solution to this tossing brake fluid dilema

Find the fluid you like in the size container that you like and calculate how many brake fluid changes (complete system) the container will complete with a drop or two to spare. Determine how many bikes you can do a complete brake flush service on with the amount of brake fluid you buy. Now the fun part, add a few bikes or the unmentionable, subtract a few(with hydraulic brakes) to the collection until you have an adequate supply of bikes to use all the brake fluid in the container of choice every year.

I personal have a Beer Keg size new brake fluid container and may have to add a half keg if I keep up the pace on bikes coming home with me. I have gotten a little over zealous with my brake fluid purchase resulting in a lot of bikes that drink the stuff so I may try to stick with just one and one half keg of brake fluid.

 

[mlytle]

Shops buy brake fluid by the gallon. Do any of you really think they crack open a fresh gallon for each bike they service?

Ah no, but they probably use that whole gallon in a day of work, they don't open it, then store it away for a year or two until next fluid change.

 

[gsaddict]

An inexpensive tester

http://www.ebay.ca/itm/361587748261

 

[AntonLargiader]

Ah no, but they probably use that whole gallon in a day of work, they don't open it, then store it away for a year or two until next fluid change.

Yes and no. Not in a day, but in a fairly short period of time. But you and others illustrate my point well... there's no need to be dogmatic about the sealed, unopened container bit.

BTW as far as stopping power and brake fade go, I have bikes come into the shop with opaque brown ink in the system and none of these guys have ever had brake fade issues. They might be trashing their brake lines and master cylinders, but the only braking problems that actually happen are from clogged bleed ports in the MC or bad hoses.

 

[Omega Man]

Yes and no. Not in a day, but in a fairly short period of time. But you and others illustrate my point well... there's no need to be dogmatic about the sealed, unopened container bit.

BTW as far as stopping power and brake fade go, I have bikes come into the shop with opaque brown ink in the system and none of these guys have ever had brake fade issues. They might be trashing their brake lines and master cylinders, but the only braking problems that actually happen are from clogged bleed ports in the MC or bad hoses.

That's the way I think about it
Being and involved in vehicle service for some time, I remember when the only messing with brake fluid was during a repair- where some was lost.
OM

 

[alancoles]

...as far as stopping power and brake fade go, I have bikes come into the shop with opaque brown ink in the system and none of these guys have ever had brake fade issues. They might be trashing their brake lines and master cylinders, but the only braking problems that actually happen are from clogged bleed ports in the MC or bad hoses.

Anton, would it be fair to suggest that the only reason they haven't experienced bake fade (with brake fluid in that condition) is because they really don't use their brakes in any extreme / severe-duty situations (probably 99.x% of us 99.x% of the time).

Unless one is doing extremely spirited riding (especially in the mountains) or doing a track-day etc., where thermal-load will build to the point of boiling things, than I'm not sure there would be an appreciable difference in the initial stopping distance from say 80 mph (things will be mushier but if the lever doesn't hit the bar there is still good pressure). It's only when there are repeated stops or scrubbing of speed that I've seen thermal loads get to the point of boiling old fluid (not the brake fluid, but the water it has absorbed). Towing a trailer, two-up and loaded changes things.

As mentioned, the greatest reason for changing brake fluid on a 1-3 year basis is to avoid/reduce deterioration of the internal braking system (MC, piston, bore, orifices, etc.). My feeling is that even if you only get twice the lifespan from these components by doing a fluid change every 3 years, the long-term cost of doing the fluid changes, even if you paid a shop to do it, would be far less than the cost of a brake system rebuild. Spend a little now or spend a lot later. YMMV

 

[AntonLargiader]

Towing a trailer, two-up and loaded changes things.

In the mountains, could be. That's the only real sustained braking you're likely to see.

Don't get me wrong... I'm a proponent of good fluid changes and I typically exceed the frequency that the published schedules dictate. But problems from using fluid that isn't from an unopened container just aren't there, at least not in my area. I buy fluid by the gallon and it looks pretty much like new when I replace it a year or two later. If I felt like adding complexity to my life I could buy a tester and test it as some sort of ongoing research problem but I think I'll pass.

 

[mlytle]

for me it boils down to...(no pun intended)

brakes are a critical safety item. i want them to work predictably to the max, everytime i use them. everytime. no surprises.

i do not skimp on safety items.

brake fluid is stupid cheap. even the most expensive kind is stupid cheap in the tiny quantities used in a bike, or even a car.

change often....toss the stuff over a month old.

no downside.

a bottle of good microbrew costs about the same as a pint of brake fluid. how many beers do you rent in a week? would you open a bottle of beer, drink half, put the cap back on and store it on a shelf for next time you are thirsty?

 

[K7GLE]

Thanks to all...last point very convincing: New brake fluid for Scout (and a fresh Moose Drool for me) every time from here on out.

Where does one find containers smaller than a full pint? (Of brake fluid, that is.)

By the way, this is probably the only forum of any kind I've ever seen that has posted NO flame-type responses to a pretty stupid question.

Double-thanks, folks!