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Possible drop of water in brake fluid, problem?

I changed my brake fluid today, and I couldn’t find a glass jar so I grabbed a empty milk jug, rinsed it out and used that to put the old brake fluid in with the turkey baster. Afterwords I had realized that there is a possibility that water droplets could have stuck to the turkey baster and got back it the fluid. The turkey baster did not touch the bottom of the jug but If a little water did get on the stem of the baster would it be a problem?

If you DID get water in the brake fluid and you live in a region that gets below freezing at night you may have a very serious problem… ice in the brake lines.

If not, and you got water in the brake lines, you may experience rusting in the lines… also not good.

If neither case exists, you may experience boiling of the fluid on one of those long descents.

In short, you do NOT want water in the lines. The problem here is that you don’t know if there actually is water in the lines. My recommendation is to purge the system and refill it. Better to err on the side of safety. Others may disagree.

If the amount of water that might stick to the baster got in my fluid, along with all new fluid, I wouldn’t be worried.

I wouldn’t worry about it.

The turkey baster tube only touched the neck of the rinsed out milk bottle.

So very little moisture was transferred from the neck of the milk bottle to the turkey baster.

And the turkey baster wasn’t submerged into the master cylinder when it was refilled…


I should mention that I didn’t bleed the system when I changed the brake fluid, just got all I could out with the turkey baster then added fresh fluid. Does that change your opinion at all?

It does. It would seem to present an opportunity for less water to have gotten into the system. You might want to empty the reservoir the best you can with a clean baster and refill it with fresh fluid.

My original understanding might have allowed water to get into the lines, and that can cause ice crystals. Ice crystals can cause loss of braking. My understanding by the new post alleviates my original concern.

While I agree its nothing to be concerned about, you did not change the brake fluid though. The old dirty fluid is still in the calipers and brake lines. So I think this would just be a good time to go ahead and flush the lines.


That’s not something I’d worry about myself. Best to keep water out, but a single drop, life’s too short to worry about that. IMO anyway. Brake fluid is usually alcohol based, so attracts water like rice attracts white. So by its nature it gets a little water in it every time you open the system anyway, like when you open the cap to see how much fluid remains. From the water vapor in the air. And probably some water gets past the seals over time. So all in all you got an extra drop to begin with. An imperfect world, but I expect you got more things to worry about than that.

If you want to worry, worry about someone accidentally finding and using the turkey baster for preparing thanksgiving dinner. That would be a very bad thing to happen. Suggest to mark it “for garage use only”.

Actually brake fluid is gylcol based, similar to anti-freeze, and is designed to mix with water to avoid line freezing. Don’t worry about the droplet. Agree with @Bing, worry about the dirty brake fluid still in the calipers, lines and wheel cylinders.

What you did was always my first step to changing brake fluid. Remove the reservoir fluid (I use a hand vacuum pump) and replace with fresh fluid from a brand new bottle. I then bleed each corner until clean fluid comes out. Add a bit more to the reservoir and button it up.

I took it for a drive and it seems like I have to press harder on the brakes for it to come to a complete stop now, it it possible this is from the water in it or (hopefully) just in my head?

It’s not the water. The problem with water in brake fluid is that it can encourage corrosion, and that it lowers the boiling point so that after HEAVY use the brakes would be less effective. Brake fluid by its nature absorbs moisture from the air (‘hygroscopic’), that’s the reason it should be changed periodically. That’s also why a tiny amount added to fresh brake fluid should cause no problem, it’s not unusual to have some in there after a while.

To make sure I understand, you did not use the baster to put in new fluid, right? The only contact with water was from whatever small amount might have been transferred from the rinsed out milk jug, correct? If so, I can’t imagine a significant amount of water made its way into your new fluid. Even if some did early on, it would have been removed with the rest of the old brake fluid.

No, it is not the water. If you installed new pads, they might need a little time to bed-in, otherwise, yes, its in your head.

Most of us have had the “in your head” problem, too. It is how $300 cold air intake kits or performance mufflers are sold. They don’t really increase HP a bunch… they SOUND like it, but the feel is in your head 'cause you spent $300.

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No I just poured it in, but I did add a little to much and so at the end did use the baster to remove a little.

You have two obvious choices : relax and drive on because most people here don’t see a problem - Have a shop do a brake fluid flush so you have piece of mind and don’t wake in the middle of the night wondering if you car will stop.

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Absolutely correct. I stand corrected. Glycols are chemically similar to alcohols. Glycol molecules are sort of double-alcohols. Two alcohols joined together.

For example, Ethylene-glycol is (CH₂OH)₂. While Methanol (Wood alcohol) is CH3OH

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Whoa, bio-chem flashbacks! from a loooong time back! :grinning:

Gives me a headache just thinking about it … lol.

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