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Brake Fluid Change?

RRMach1

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Hey everyone, got a quick question for you all. When did you change your brake fluid? My Mach 1 is a 2021 but only had about 10k miles on it, is it worth it to change the brake fluid yet? Or should I wait until the recommended mileage interval?
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murick

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Brake fluid change interval is usually based on time, and that depends on the average humidity in your area.

I change mine based in the indications from my cheap tester that I bought on Amazon.
https://www.amazon.com/Aicevoos-Tester-Strips-Calibrated-DOT-5-1/dp/B0C1SFRRGB/ref=sr_1_2?crid=UX9YY0CUBG5Z&keywords=Brake+Fluid+Tester+-+calibrated+for+DOT+4&qid=1708289440&s=automotive&sprefix=brake+fluid+tester+-+calibrated+for+dot+4+,automotive,139&sr=1-2
Do you know what does it measure actually?
 

1004ron

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I believe conductivity due to retained moisture - It correlated with my old Fluke 77 resistance measurement.
 

xcm77

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I changed mine after 3y, right after I almost had an incident at the track where the pedal went all the way to the floor and the brakes said "bye bye". I was very surprised to see the fluid being quite dirty. YMMV based on a few factors like humidity, abuse, heat, etc. but if you don't track the car at all, you should be good with the manufacturer provided maintenance intervals. If you do track it however, think about getting a sample to see how it looks or simply change it more often.
 
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murick

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I believe conductivity due to retained moisture - It correlated with my old Fluke 77 resistance measurement.
I guess there might be different reasons for changing the brake fluid then, which are quite independent.
  1. The water in the fluid which I would expect is probably absorbed from the air in the reservoir, so this would be something affecting the fluid which is actually not used.
  2. The changed properties of the fluid because of the heat from the calipers.
I do not believe these two can actually mix during the usage, but you probably want to change the fluid when either gets compromised.

What I am trying to say is that measuring the moisture is just one part of the question the OP should be asking. The other one is actually how much he cooks the fluid in the calipers.
 

Hifiguy

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Hey everyone, got a quick question for you all. When did you change your brake fluid? My Mach 1 is a 2021 but only had about 10k miles on it, is it worth it to change the brake fluid yet? Or should I wait until the recommended mileage interval?
Not sure why a lot of folk in this thread think brake fluid is trashed after water absorption. All brake fluid will be saturated with water after a couple years, they will still work after though. A lot of brake fluids specify wet braking temp before boiling. Pick a fluid that does well if you’re concerned about this (Castro SRF).

If you track your car, every year do a brake flush.

If street, do it like any other car. replace when fluid is dirty or brakes are soft after repeated use. Or follow the interval, whichever first.
 
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kz

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If you track your car, every year do a brake flush.

If street, do it like any other car. replace when fluid is dirty or brakes are soft after repeated use. Or follow the interval, whichever first.
This. Don't overthink it, especially if you street drive, your brakes will be fine, you won't boil the fluid on the way to work.
 

Southview

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Order some brake fluid test strips and then decide.
 

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paulm1

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Hey everyone, got a quick question for you all. When did you change your brake fluid? My Mach 1 is a 2021 but only had about 10k miles on it, is it worth it to change the brake fluid yet? Or should I wait until the recommended mileage interval?
Do you track the car?
 

1004ron

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Not sure why a lot of folk in this thread think brake fluid is trashed after water absorption. All brake fluid will be saturated with water after a couple years, they will still work after though. A lot of brake fluids specify wet braking temp before boiling. Pick a fluid that does well if you’re concerned about this (Castro SRF).
My recommendation is for folks here to search for a reliable source, and the results will most likely contradict the advice offered above.
Why Is Moisture in the Fluid a Problem?
If street, do it like any other car. replace when fluid is dirty or brakes are soft after repeated use. Or follow the interval, whichever first.
Dirty - what's the criteria?

Or they just fail at the most inopportune time.
 
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Brooski1

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Some HPDE sponsoring groups, including PCA, require proof of a yearly fluid change. For a street car every 2 years should be fine.

1708361033047.png
 

Hifiguy

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My recommendation is for folks here to search for a reliable source, and the results will most likely contradict the advice offered above.
Why Is Moisture in the Fluid a Problem?

Dirty - what's the criteria?

Or they just fail at the most inopportune time.
Brake fluid saturated with water will not cause an immediate failure. To be honest, checking for cracks or old brake hoses/rusted lines is way more important than wet BF. Wet BF will have a lower boiling point, ie your brakes get softer quicker after repetitive use. So there will be signs.

The brake reservoir also feeds the clutch line in these cars, so if you have a MT the fluid will get dirtier faster.

Attached the maintenance interval, ford lists every 3 years:

1708375973094.png
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