Bonehead move - poured washer fluid in brake fluid receptacle

TaycanCook

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I read a Rennlist post by a track driver who recommended Pentosin. I can get it here at the parts store, so am good to go.
Sure. Whatever your favorite dot 4 fluid is. People are partial to motul, super ate, etc.
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TDinDC

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I would still have the system flushed. Brake fluid is a funny thing. I have never had a problem on the streets, but I once had my brake fluid boil during a race and it was terrifying. You likely would not experience it, but why take that chance?

It's a tedious job to flush brakes if you don't have the right tools (I'm so lazy I think it sucks and I have all of the tools). Just fill with dot4, take to dealer, and pay to have the whole thing flushed and filled with Porsche OEM fluid. Enjoy the car wash.
 
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TaycanCook

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I would still have the system flushed. Brake fluid is a funny thing. I have never had a problem on the streets, but I once had my brake fluid boil during a race and it was terrifying. You likely would not experience it, but why take that chance?

It's a tedious job to flush brakes if you don't have the right tools (I'm so lazy I think it sucks and I have all of the tools). Just fill with dot4, take to dealer, and pay to have the whole thing flushed and filled with Porsche OEM fluid. Enjoy the car wash.
I'm willing to bet that the car is very unlikely to be in that situation. With the majority of braking being Regen and only low speed mechanical braking coming on with the exception of letting the car sit for a while. He's more than likely ok.

If this car sees hpde, sure, go ahead and bleed away. You're likely doing that any way as part of regular hpde maintenance.

At the end of the day, whatever that gives you the peace of mind you need.
 

TDinDC

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I'm willing to bet that the car is very unlikely to be in that situation. With the majority of braking being Regen and only low speed mechanical braking coming on with the exception of letting the car sit for a while. He's more than likely ok.

If this car sees hpde, sure, go ahead and bleed away. You're likely doing that any way as part of regular hpde maintenance.

At the end of the day, whatever that gives you the peace of mind you need.
As I myself said, he is likely not to see the situation I mentioned.

But brake fluid is like blood. If you inject Hep B into blood, the blood is likely contaminated even if the contamination liquid was yellow and you "think" you got it all out. It just doesn't work that way. You can't see it. And once it is contaminated, the boiling point can be dramatically lowered. Again, you just can't see it.

And I don't think that it's fair to say that you don't worry about brakes so long as you are only driving on the streets. Sure, the chances are much lower that you will heat up your braking system to the failure point but (1) if you do the results could be catastrophic and life changing/ending; and (2) once you are in the situation, it is too late.

It's just the cost of a brake flush. Not much. I just think this is not a situation where I think people should "f@ck around and find out".
 

BJCanadaMax

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Have you thought about sending it to the dealership to service it?
 


Marmolata

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My brake fluid cap has very specific instructions on it, written in bright yellow text.
 

bsclywilly

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As others have said, empty the reservoir with a turkey baster ASAP and refill with brake fluid.

Brake fluid is hygroscopic meaning it will absorb moisture, reducing the boiling point. If you limit the time in contact with the water/glycol washer fluid maybe you can avert crisis. But a full flush would be in order sooner than later. Again, it’s for safety in an emergency situation that you’ll need it.

There are cheap brake fluid testers available on Amazon if you need to check how much water absorption happened. But I’d still do the full flush as the moisture can also lead to corrosion internally over a longer time period.
 

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Do the baster thing, then drive it to the dealer and have them flush the system and replace the fluid.
 


JAGMAN

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I’d do the flush. Oil tends to float on water, which means water sinks deeper into the system.
 

Fish Fingers

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I would flush too.

Imo, it's a bit like driving around with a damaged tyre that seems ok, but may explode if you hit a pothole at high speed.

Or it may not.

But you don't know.

Its not worth having that thought pecking your head (which it will) until the car gets it's next service.
 

FlyingPoint

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Let's look at this problem analytically:

First, we measure brake fluid effectiveness by its "wet boiling point". Second, the threshold to reach this point is about 3%. Any moisture absorbed at or above this percentage could cause the brake fluid to boil under high heat. Because brake fluid is hydroscopic, it will naturally over time absorb moisture from the atmosphere. Average absorption is about 2% per year. My personal experience verifies this using my brake fluid tester. This is why Porsche recommends flushing every two years.

The OP has indicated that approximately 1 oz of water contaminated the brake fluid. The brake lines hold about 1L of fluid. The math works out to >3% water. This does not consider the percentage of moisture already in the system due to the passage of time.

The above strongly suggests a flush with a properly rated brake fluid.
 

Vercingetorix

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I would not be concerned the tiniest amount by the addition of water to the system. The addition of chemicals in the washer fluid interacting with the rubber in the brake system would concern me 100%.
Porsche Taycan Bonehead move - poured washer fluid in brake fluid receptacle F8EA656A-595F-47E3-886E-D4F8A4DEBEBE
 
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4thPcar

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OK everyone I removed 99% of liquid from the reservoir and the car has not moved since I discovered the problem. I have refilled with DOT4 and plan to do a brake flush for added safety. Thanks to everyone that weighed in.

I learned an expensive lesson. Don't listen to tunes on my earbuds while multi-tasking while replacing fluids in my car.
 

FlyingPoint

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OK everyone I removed 99% of liquid from the reservoir and the car has not moved since I discovered the problem. I have refilled with DOT4 and plan to do a brake flush for added safety. Thanks to everyone that weighed in.

I learned an expensive lesson. Don't listen to tunes on my earbuds while multi-tasking while replacing fluids in my car.
We all make these kind of mistakes, its not if, its when. I remember doing a standard flush on my GT3 and really screwed up due to distraction. I was using a Motive bleeder (air only) and ran the reservoir dry. That was an expensive mistake. We all make them. My comments were aimed at only trying to keep you safe, albeit with a bit of levity sprinkled in! Did I ever mention running my GT3 off the trailer because I forgot to pull out and affix the ramps? There is no end to the stupidity that we can do. Good news, we learn and hopefully don't repeat.
 
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4thPcar

4thPcar

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For anyone still following....I took my car - reluctantly (had bad experiences in the past) - to a San Diego dealership that offered me an appointment today for the brake flush. I asked them to call me before I came down for an estimate; of course they didn't. So I showed up, and they quoted me $585. That's right.

So I walked out and drove up to my preferred dealership (in Carlsbad) that had told me before they were booked all month. The SA got me in and called me an Uber to drive me home. He said the charge would be $315 and that I'll get a military discount bringing it under $300. They will send an Uber to pick me up tomorrow to collect the car.

It's hard to believe two dealerships could be so far apart in price, one charging almost twice as much. If you live in San Diego, I hope you'll benefit from this finding.
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