Hydraulic brake and clutch systems use a water soluble fluid. The ability to absorb water has its advantages and
Every time you open the top of your fluid reservoir, contact is made with the atmosphere (air). There is water included in that air! The brake fluid will, over time, absorb the water in the air that is sitting above the fluid in the reservoir. Next time you open it, a fresh batch of air with its water is introduced and the fluid begins absorbing it all over again. That is why they now make the reservoirs translucent, so you can view the fluid level without removing the cover and letting more air in!
Once water is in your hydraulic system it does harm in more ways than one. The most important to me is the reduction of hydraulic efficiency. You see, water is more compressible than oil. So, you get a squishy pedal.
Water is not good for the system and thank goodness the brake fluid is good at absorbing it and bringing it out of the system if it ever finds any. All you have to do is remove the fluid and you'll be removing water from your system.
How do you know when it is time? Brake fluid turns from the light, clear look it has as new to a dark opaque appearance when contaminated with water. It is that easy to tell if it is time to remove your moisture.
Don't want to have to bleed the system? Me neither!! That is why I've done it this way and that is why I'm sharing it with you! Because I love you! You see, just when you wondered why you felt so alone, you find out that some guy named GARY that you have never met and probably never will, cares about you. Have a nice day and enjoy my advice!
Buy some *new brake fluid. It is sealed for a reason, it absorbs moisture from air. Make sure it is compatible with what is in your system. Most reservoirs have the type of fluid printed on the cover. Example: "Use only DOT 3 fluid." Then just buy a two 12 oz. cans or one larger can of DOT 3 or whatever type of fluid you need.
Buy a Turkey Baster. For those of you reading who don't know what that is, it is a tubular vessel about ten inches long with a taper on one end and a rubber bulb on the other, used for basting meet while cooking. It looks like an oversized eyedropper or ear dropper. Take it home and put it in your kitchen. Now take the old one out of the kitchen and to your car after cleaning and *drying it very thoroughly. Your cook should be happy that you thought of her/him.
Using an old brake fluid can for transfer to proper disposal facilities, use the baster to remove the brake fluid from the reservoir. Put it in the can. Don't spill on anything since brake fluid is corrosive to a lot of things. Use a rag or newspaper as a drop cloth around the reservoir area that you are working in. Remove as much of the fluid as you possibly can.
Now clean the reservoir and reservoir cover using a very clean cloth or paper towel. Do not leave any particles of lint or dirt in the reservoir or on the cover. Get it as clean as you can.
Now pour new fluid to the high level indicator. Cover and drive for a few days. The new fluid will marry with the old fluid that was left in the brake lines and slave cylinders (the parts of the system that you did not drain). The new fluid will absorb from the old fluid, water until the new and old fluids are containing the same percentage of water each.
Now it is time to do it again. Get out the baster and the disposal can. This time you may not even have to do the wipe clean. Just replace that fluid in the reservoir and start driving again. Eventually you will have diluted the water content in the system to a point that your fluid will remain clear looking, no water! Ok, more properly said, "an insignificant amount of water."