Question for Tom, F&L GoR

[TrackAire]

Hi Tom,

If you open a new bottle of brake fluid (say 12 oz) and only use a half of it, does having the newly intoduced air chamber on top of the fluid harm it in any way for future use?

I just flushed the clutch and only used about 6 oz and put the cap back on. Is this stuff good to use after 6 weeks or so of storage?

I know brake fluid absorbs water, is air also a problem assuming it is "dry" air?

I used decent quality brake fluid today, but some of the higher end Castrol stuff is over $70.00 a bottle. Would it be beneficial to purge the top of the left over fluid with CO2 or nitrogen (have CO2 available at work) before putting the cap back on and putting the bottle on the shelf for future use?

Thanks in advance,

George

 

[steve911]

Your question reminds of the days when I was much younger. Back then (1968) I had recently bought my first car to fix up and drive. It needed paint and I took it to a family friend who did paint jobs in his garage. Back then all of the paints were acrylic enamel single stage (meaning that they dried by evaporation).

Whenever the painter finished a job and there was paint left over in the can, He would take a deep breath hold it as long as he could, and then forcefully exhale into the paint can with the lid partially on and then quickly close the lid. Being young and niave at the time I didn't know why he was doing it. Turns out by holding his breath and then exhaling into the can he was displacing the oxygen that would have been present in the can had he simply closed the lid and the paint didnt skin over or start to dry up.

The process actually works. I do it to this day with house paint and varnish cans, and there is a noticeable difference in shelf life.

the process I use with plastic bottles is I simply squeeze the sides of the bottles thus displacing as much air in the bottle as possible.

 

[dave6666]

Whenever the painter finished a job and there was paint left over in the can, He would take a deep breath hold it as long as he could, and then forcefully exhale into the paint can with the lid partially on and then quickly close the lid.

I would wake up hours later with a paint can impaled on my face LOL.

 

[TrackAire]

Thanks for the idea of air displacement on other stuff like paint. Thats thinking outside of the box.

I hate brake fluid, it damages paint, feels funny on your skin and if I ever spill a fluid, it always seems to be brake fluid.

Maybe Tom will be able to chime in on this too regarding brake fluid storage after opening the bottle.

Cheers,
George

 

[Tom F&L GoR]

I'm sorry, George, with all my posting yesterday I thought I did reply, but guess I didn't hit the right send button.

Condensed version:
Brake fluid doesn't deteriorate due to contact with water, it is contaminated. Luckily, the amount of air above the fluid inside the bottle can't contain enough moisture to make any difference. However, an opened bottle that is re-closed will try to breathe from warming and cooling every day. Over time it might absorb enough moisture to be detrimental. I suggest you simply close the bottle and put the bottle in an air-tight baggie. The baggie will expand and contract, but since it is flexible, won't exchange any gases. To go one step further, close your bottle, put it in the baggie, and fill the baggie with the inert gas. Then even if the can breathes, it is only the dry gas it comes in contact with. That should make shelf life exceedingly long.

(Perhaps someone can comment on the permeability of CO2, N, or other inert gases out of plastic bottles and baggies; as well comment on H20 passing into the same materials.)

This is different than the paint. I think the paint, once in contact with oxygen, begins a polymerizing reaction. Once the reaction starts, it keeps going, slowly, inside the closed can. In this case, displacing the O2 from the air with CO2 from the breath would delay the onset of the reaction. Similarly, an inert gas over the paint should stop it also.

Note that the "breath" trick isn't good for brake fluid since your breath contains moisture, or in the case of Dave, beer.

 

[TrackAire]

Thanks Tom,

Your input and knowledge is much appreciated!!

Cheers,
George

 

[LiquoRT/10]

An inert gas that is widely available to preserve open wine bottles should probably do the trick.
Cost about 15 bucks with over 100 uses per can.

 

[dave6666]

I just looked at a bottle of Prestone DOT 4 that I have, and the bottle is HDPE (High Density PolyEthylene).

HDPE has excellent water barrier properties, so going through the vessel wall should be of no concern.



I apologize that I have actually posted something useful.

 

[99 R/T 10]

Note that the "breath" trick isn't good for brake fluid since your breath contains moisture, or in the case of Dave, beer.

 

[dave6666]

If you are concerned about water vapor bypassing the paper seal on the bottle cap wrap that area with Parafilm. I use it for sealing biological samples from contamination in transit to the analytical lab. It will work for your application of the brake fluid bottle.

Parafilm - Wikipedia, the free encyclopedia

I use it on my beer bottles too - frosty and fizzy the next day!


















OK. That last line was a lie. I never have leftover beer!