2 Year Brake Fluid Changes--Overkill?

[Ihatetochangeoil]

The fluids mix fully. Brownian motion.

If you do the reservoir, you will drop a 4% (water content) system to 2%, do it twice and you drop to 1%. It's the same as a partial drain/fill in any system, really. It's tested, and works. You can demonstrate this yourself in your driveway with calcium hydride strips or test pens. Over time (and it's not a lot), the water content in the calipers will equal the content in the reservoir.

I'll make this simple and straightforward: I don't believe you. I'm not calling you a liar, but I'm thoroughly convinced you're mistaken. Now, since I'm not a scientist nor an engineer, I'd call myself a country boy with a little common sense, here's what I challenge you to do: Do your "turkey baster" in your reservoir, make yourself happy, and bleed one brake (anywhere). Just bleed a little dark fluid, a 7ml syringe is enough. All you really need is one good drop. Keep the fluid you bled for reference in a tightly sealed container. Then drive the vehicle for 6 months or however long YOU think it will take for "Brownian motion" to take place, then resample the same brake as you did when you changed the fluid in MC. Post your results, and back up your results with test strip photographs. PM me your address and I will even mail you a few Phoenix Test strips I have on hand, so it will cost you zero. https://www.amazon.com/Phoenix-Syst...rds=phoenix+test+strips&qid=1609362973&sr=8-2 Prove that you're right?
No hard feelings; I wish you Happy New Year sir.

 

[Oro_O]

I'll make this simple and straightforward: I don't believe you.

No problem! I know it sounds weird unless you have studied the science a bit, or read about it somewhere.

I have tested it myself with the results I listed above (dropping H2O content). Others, have, too and it's on the internet. So there's real-world evidence as well as "theory." I've got a really busy day today but at some other time I'll go into detail on it, maybe make a fresh, informative test.

here's one simple analogy I can make that might help you get the picture. Imagine this:

a) Take a gallon of Coca Cola and put it in a five gallon bucket.
b) Now add a gallon of Orange soda VERY slowly on top of the coke. (I like Orange Crush myself...)
c) Notice how they orange crush floats on top of the coke and they don't mix? Nope, it doesn't.
d) They will mix 100%, top to bottom in the container. This is called "brownian motion" among other things. Fluids that have very different chemistries - like oil and water, won't mix. But if they are "miscible" they mix fully over a short time.

The same thing happens over time in the brake system. Water in calipers will be re-distributed to the fresh fluid elsewhere (because the fluid and water are miscible (fully mixable) - just like Orange Crush and Coke.

I get that this sounds odd at first but it does work this way. No offense taken.

 

[Ihatetochangeoil]

I've got a lot of issues with your statements. A modern sealed braking system with a MC, curved and convoluted lines, an ABS module (with non-serviceable filters built in) and remote slave cylinders with bleeder screws is a far cry from a 5 gallon bucket; and brake fluid vs water don't "mix."
Here is a picture of old used brake fluid and water in a beaker on my kitchen table. If I stir it and then leave it alone again for a few minutes it will separate again. In fact, everything you've said is soo far off base and not even pertinent to a braking system, I'm not even sure why I'm responding to you. If this is the best you've got to respond to me, I see no point in continuing this discussion. I did not ask you for an "analogy." I asked you to prove your unfounded statement with a real world experiment. In closing, I guess I shall take your "analogy" as a no.

 

[nobb]

I remember on two Fords that our family bought new, the first brake flush was performed after 6-7 years and it came out green which was a bit horrifying. That was the point that I started changing brake fluid every 3 years religiously on any vehicle. I know most people likely never change their brake fluid and I don't think I've ever heard of a brake fluid related failure, but just because it still works find doesn't mean it's not slowly corroding away the internals.

 

[MrPlow]

I've got a lot of issues with your statements. A modern sealed braking system with a MC, curved and convoluted lines, an ABS module (with non-serviceable filters built in) and remote slave cylinders with bleeder screws is a far cry from a 5 gallon bucket; and brake fluid vs water don't "mix."
Here is a picture of old used brake fluid and water in a beaker on my kitchen table. View attachment 38623 If I stir it and then leave it alone again for a few minutes it will separate again. In fact, everything you've said is soo far off base and not even pertinent to a braking system, I'm not even sure why I'm responding to you. If this is the best you've got to respond to me, I see no point in continuing this discussion. I did not ask you for an "analogy." I asked you to prove your unfounded statement with a real world experiment. In closing, I guess I shall take your "analogy" as a no.

Regardless, it's not like bleeding the brakes once every couple of years is a huge task. With proper tools, it can go pretty dang fast! If one is also so inclined to rotate the wheels, then that would be a prime time to pump some fresh stuff into the system.

I neglect my brake fluid far more than most, and never had problems with brakes. So, I can see how if someone just swaps the reservoir fluid once in a while, it's no worse than what I have done in the past.

 

[350Rocket]

I keep all my vehicles to at least 200k miles. Haven’t changed brake fluid since the early 90’s. Haven’t had an ABS controller failure, nor had to replace any brake hoses or caliper pistons. I’ll keep doing what I’ve been doing.

Lots of people neglect maintenance and get lucky. Good for you. I hope you continue to get lucky.
I got lucky my system held up okay besides one failed caliper in 15 years 200k miles. My employer owned the truck before me and we only did repairs as needed for the most part.

When I had the brake fluid flushed a week ago the fluid looked like someone threw up in it. Disgusting looking. I wouldn't take my chances with really old fluid in one of these with abs modules.

 

[Blinker]

Lots of people neglect maintenance and get lucky. Good for you. I hope you continue to get lucky.
I got lucky my system held up okay besides one failed caliper in 15 years 200k miles. My employer owned the truck before me and we only did repairs as needed for the most part.

When I had the brake fluid flushed a week ago the fluid looked like someone threw up in it. Disgusting looking. I wouldn't take my chances with really old fluid in one of these with abs modules.

Cool.

 

[Burt]

I did a flush on my two cars yesterday and wondered the same thing. Is it really worth it as I don't hear about lots of brake failures and I know most people either never flush brake fluid or maybe when they have a brake job done. I looked it up - it's $100 to have it done, so if you keep the car 15 years, that's $700. So questionable benefit if you don't do it yourself.

I did a halfway job of flushing a few years ago, so I got a manual pump this time and it worked better. On the Lexus, the fluid looked so clear, you could hardly tell the new vs old. The Fiesta's fluid was green-gray color and I suppose that means bacteria was growing in it?

Same thing for oil changes. Lexus looks clear red-ish brown and Fiesta is muddy brown.

But the way, you guys where salt is being used, how much difference does it make to flush since it's a closed system and all the corrosion is on the outside? Seems like southern humidity would be more of a concern.

 

[Oro_O]

I've got a lot of issues with your statements

Well, so much for being polite, what an intemperate mess you made there.

As long as the fluids are in contact, there is no difference. Does not matter if the contact is via a tube or in the same bucket. Again, this is science.

The info is out there, just google it. I can't do your homework for you today!

 

[artbuc]

I've got a lot of issues with your statements. A modern sealed braking system with a MC, curved and convoluted lines, an ABS module (with non-serviceable filters built in) and remote slave cylinders with bleeder screws is a far cry from a 5 gallon bucket; and brake fluid vs water don't "mix."
Here is a picture of old used brake fluid and water in a beaker on my kitchen table. View attachment 38623 If I stir it and then leave it alone again for a few minutes it will separate again. In fact, everything you've said is soo far off base and not even pertinent to a braking system, I'm not even sure why I'm responding to you. If this is the best you've got to respond to me, I see no point in continuing this discussion. I did not ask you for an "analogy." I asked you to prove your unfounded statement with a real world experiment. In closing, I guess I shall take your "analogy" as a no.

We are talking about dissolved water, not separate phase water. Dissolved water in brake fluid will equilibrate the same way that humidity in your house does. It is basic thermodynamics as the system looks to minimize its free energy.

The process of equilibration is diffusion which is not caused by Brownian motion. Brownian motion is random movement. Diffusion is a solute transporting from high to low concentration to minimize free energy.

Now, if I have a terribly neglected system which had a few drops of phase water pooling in the caliper, I want it out of there fast. I could do the turkey baster and wait. Eventually the phase water will be reabsorbed and moved out of the system. How long that takes will depend on your driving habits and how often you baste the turkey. I am too old to wait that long.

 

[doublebase]

I work with some very meticulous techs, yet none of them change their brake fluid. Unless of course they are removing a caliper or something. I’m talking guys that change their oil every 3,000 miles with synthetic. Guys that change their diff fluid every single year, along with the transfer case. Guys that change their transmission fluid once a year and spray silicone on their axle boots. Guys that maintain things just for the sake of maintaining them, yet none of them change their brake fluid.

You should see some of the tires they have thrown away off of their cars...I’m looking at them like...you could get another 10,000 miles out of these, easy. And struts, ball joints and tie rods?? I swear if they feel even the slightest thing up front, the whole suspension gets replaced. These are cars you WANT to buy used, but no brake fluid changes.

But reading this thread makes me want to do mine. Honestly.

One of these guys^^owns a 2008 Toyota Tundra. New frame. You should see how this thing has been maintained...the differential fluid and trader case fluid he drains from it every year looks so new, that you’d want to keep it and put it back in the bottle. I’m dying to buy this truck but the guy won‘t sell it.

 

[meep]

I no longer recall the specifics, it has been awhile since this happened.

I’d wager that in all 3 cases I tried, the dot 3 was oem, but again it’s been 20+ years for me. 75% chance I was using prestone fluid, as thats generally what I’ve always gone to.

 

[supton]

I get the idea of Brownian motion but it's a looong ways from the master cylinder to the rearmost caliper.

 

[artbuc]

I get the idea of Brownian motion but it's a looong ways from the master cylinder to the rearmost caliper.

Brownian motion has nothing to do with this but thermodynamic diffusion will make it happen.

 

[The Critic]

I work with some very meticulous techs, yet none of them change their brake fluid. Unless of course they are removing a caliper or something. I’m talking guys that change their oil every 3,000 miles with synthetic. Guys that change their diff fluid every single year, along with the transfer case. Guys that change their transmission fluid once a year and spray silicone on their axle boots. Guys that maintain things just for the sake of maintaining them, yet none of them change their brake fluid.

You should see some of the tires they have thrown away off of their cars...I’m looking at them like...you could get another 10,000 miles out of these, easy. And struts, ball joints and tie rods?? I swear if they feel even the slightest thing up front, the whole suspension gets replaced. These are cars you WANT to buy used, but no brake fluid changes.

But reading this thread makes me want to do mine. Honestly.

One of these guys^^owns a 2008 Toyota Tundra. New frame. You should see how this thing has been maintained...the differential fluid and trader case fluid he drains from it every year looks so new, that you’d want to keep it and put it back in the bottle. I’m dying to buy this truck but the guy won‘t sell it.

So true. I also know guys who change their oil every 2,500 miles and fix the slightest oil seeps or suspension wear issues, but never change any of their trans or driveline fluids. They consider those items to be "wallet flushes."

 

[supton]

Brownian motion has nothing to do with this but thermodynamic diffusion will make it happen.

It's still a long way ways out and back. Plus hot fluid rises, so how is the hot fluid in the master cylinder (from underhood heat) going to get to the caliper?

 

[Wolf359]

It's still a long way ways out and back. Plus hot fluid rises, so how is the hot fluid in the master cylinder (from underhood heat) going to get to the caliper?

You do realize that the calipers get way hotter from the brake pads when used right?

 

[Luftmasse]

I’d wager that in all 3 cases I tried, the dot 3 was oem, but again it’s been 20+ years for me. 75% chance I was using prestone fluid, as thats generally what I’ve always gone to.

Are you able to feel the difference as in the firmness of the pedal between OEM vs Prestone?

For me, Prestone feels slightly softer.

 

[supton]

You do realize that the calipers get way hotter from the brake pads when used right?

Yes, but... IME they only get hot when seized. The times I've checked my brakes, after any sort of drive, short, long, whatever--I can hold my hand on the rotor.

Any hotter than that and I'd probably be upset with myself. Driving too hard, not using engine braking, etc.

 

[Jimmy_Russells]

Yes, but... IME they only get hot when seized. The times I've checked my brakes, after any sort of drive, short, long, whatever--I can hold my hand on the rotor.

Any hotter than that and I'd probably be upset with myself. Driving too hard, not using engine braking, etc.

Yeah, that's nonsense. Rotors get balls hot even with light driving.

Changing oil every 3k but not brake fluid at all makes absolutely no sense. Anyone who tries to justify something like that is just straight up wrong.