My dad had a 60 falcon for his commuter car. He let me use it for a date car. He warned me not to use the radio when I was riding around. I didn’t listen and the battery was dead when I tried to start it again. I got a jump and never told him. I liked that car though. Fire engine red with fresh wax.
I’ve never replaced the brake fluid just for the sake of replacing it. But everytime I work on the brakes, replacing pads/shoes, other parts, before the job is checked “complete”, usually do a brake system fluid bleed. I’d guess I replace the brake fluid in each vehicle every 3 -5 years as a result of those bleeds.
I’ve never had much trouble with the brake hydraulics in my truck or Corolla, other than the occasional master cylinder or wheel cylinder replacement. I did find a slightly obstructed rear brake line in my truck recently. But I had a good deal more of replacing stuff with the VW Rabbit’s brake hydraulics, especially the rear wheel cylinders. I’ve never seen any sign of water layering in the brake fluid I’ve drained out, but maybe I don’t know the best way to look for it.
I did brakes, batteries, filters, belts, alternator, carburetors way back, various other minor stuff. Never any need to remove a valve cover, much less a cylinder head, and no trans issues. I’ve kept my cars an average of about 9 years I guess, but I’ve only averaged around 8k miles a year. I last sold a 22 year old RAV4 (most reliable car I’ve owned) with original brake fluid, which worked perfectly and looked like new in the master cylinder. It did get one coolant change at about 15 years when the water pump got replaced, so I have to slightly amend my oil changes only statement.
There is something about the original Toyota brake fluid that does not seem to absorb moisture, most don’t fail a test strip unless flushed and then after time they will just like most others…
So using a Toyota for that example is the exception to the rule…
Is the Toyota brake fluid silicone? That might account for low water absorption.
Every Toyota/Lexus we’ve owned uses Dot-3. And Toyota OEM fluid on our vehicles di absorb water.
As far as I know it is the same stuff, but I have tested hundreds of Toyotas with very low moister content down in my neck of the woods, and it is a very humid place… In the hot summer heat as soon as you go outside you are sweating almost instantly…
I can not explain it but I had 180K on my 2006 Corolla with the original brake fluid with all the original hydraulic brake parts and it was still clear, clean and passed the brake test strip…
I have had many techs recommend brake fluid flushes as a preventive maintenance and I always asked to see the test strip and most of the time the high mileage Toyotas passed, however the ones that had replacement hydraulic parts replaced for whatever reason and had parts store whatever name brake fluid (DOT3/4) after X miles would fail the test strip… SO it is not the vehicle, it is the OEM fluid… My Vibe (Matrix) same thing, fluid clean with 125K miles with OEM fluid… Again I have seen it with lots of other Toyotas and even had other techs paying more attention to the same results… Did every one pass NO, did more pass then not YES…Again this is what I have seen over the years…
And I worked at the same company that ran 26+ locations in Nashville area alone and I worked some at about 15 locations in 2 states at one time or another for whatever reasons the last 17 years before retiring in 2021, at shops that saw everything from BMW, MB and Volvos to all the normal imports as well as the big 3 and running anywhere from 15 to 70+ vehicles a day depending on location… and over 1/2 of those years running 50+ vehicles a day including personal, commercial, fleet vehicles, GSA (government account), State and all the different law enforcements including the Secret Service, US Marshals, State Trooper, and all the rest, so I am not basing this off of a few vehicles that I have owned but thousands and thousand of vehicles over the years… And we also kept a history of all work done to said vehicles, and very loyal customers that a lot of, not all, kept there vehicles as long as possible…
Again, results may be different in FL, MH, Cali, NY and other places not around here…
Location could very well be the difference.
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That is what I am thinking also…
Maybe it’s the fluid, but could be that it is harder for water to infiltrate the system on Toyotas. About the only two paths for water to get in are through the rubber brake hoses, or through the master cylinder vent. Maybe something about Toyota’s design or materials used.
If the fluid had been changed due to maintenance/repairs not contamination then the fluid will absorb moisture like normal, I have ruled out the vehicle… I have also never bought Toyota dealer branded brake fluid (if they even sell it) to see what it does, so I don’t know if the manufacture adds anything (additive) to the fluid or not… I have never heard of it and I don’t think they do, but it something is different about it… I just don’t have an explanation for it, I can only report what I am a few others have seen here in my neck of the woods…
I just think (no prof) that Toyota fluid is more resistant to absorbing moisture… And I don’t know if the OEM fluid is any different then the dealer fluid… Who knows… lol
I wonder how water gets through hoses that withstand 1200 psi.
Toyota has a higher standard for the brake fluid used in their vehicles. This is information from an old master cylinder seal recall.
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I think moisture most likely enters through the master cylinder cap screw-on gap. It then diffuses into the reservoir of fluid and into the lines.
Toyota brake fluid is SAE J1703. No difference then the standard Dot-3 brake fluid you can buy at WalMart. The lubricants described in that information from Toyota is in ALL Dot-3 brake Fluid. It’s just wording used by Toyota to convince people to buy only Toyota Parts and fluids. That same type of wording is what Toyota says about their Motor Oil. GM, Ford and Chryco all use similar wording.
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@MikeInNH … the radio news said there was some serious flooding problem in Vermont , hope everything remains ok in your neck of the woods 
I have never seen an explanation of water in brake fluid that makes sense to me, which I suppose is the main reason I never even considered changing it.
We’re OK here. Vermont is a special place. It’s either Mountains or valleys. 6" of rain in the mountains equates to 2’ or water in the valleys. We’ve had a lot of rain here, but prior to all this rain we were in drought conditions. So now the lakes/ponds are back up to normal levels. Ground water is back up to levels. My lawn never looked so good.
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–Brake fluid can absorb moisture in a variety of ways – through the packaging process, while pouring it into the reservoir and even through the brake fluid lines.–
Yeah like I said I have never seen an explanation that made sense to me.