Brake Fluid Change

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Originally Posted by ZeeOSix
I was looking in my 2005 Tacoma Owner's Manual and there is no mention at all about changing the brake fluid. Wondering if other car makers call it out in their maintenance schedule?

I know most motorcycle manuals call out a brake fluid change in the maintenance schedule to be performed every 2 or 3 years.

So my 2005 Tacoma (only has 50K miles) still has the original brake fluid, and it still looks new (color wise) in the clear brake fluid reservoir. But I'm going to change it out anyway since it's really old. Probably should have did it years ago.

Changing brake fluid is probably even more neglected by car owners than changing coolant.
eek.gif




My Toyota dealer says every 2. I've always done 3 years. Don't have space for it myself, so will pay the $95 this spring...
 
IIRC Subaru recommends a brake bleed every 1.5 yrs, IF, you line in a humid climate and tow on a regular basis.

As for me, I bleed every two to four yrs and once/yr on motorcycles.
 
Lexus serviced the brake fluid in our GS 350 F Sport at the 60K service.
When I replace front brakes, I generally do a flush. It always improves the pedal feel.
Especially on neglected systems.
 
Originally Posted by ctechbob
Originally Posted by Zolton
I bleed mine dry, add fluid and close the valves.


Wait, what?


Gravity. Ever heard of it?

[Linked Image from i.imgur.com]


[Linked Image from i.imgur.com]
 
Originally Posted by Zolton
Originally Posted by ctechbob
Originally Posted by Zolton
I bleed mine dry, add fluid and close the valves.


Wait, what?


Gravity. Every heard of it?



From what you typed it sounded if you opened the bleeders and let all the fluid out and refilled.
 
Originally Posted by Zolton
I bleed mine dry, add fluid and close the valves.

Used cars will get a bleed even if brakes look ok. If the fluid looks nasty I'll re-do it in a year.

Otherwise it's plenty enough to just do it when replacing pads.

I noticed the new VW manual says to do first flush at 3 yr, then 2yr subsequent. This is consistent with my thinking that new parts will not even have any corrosion to resist.

[Linked Image from i.imgur.com]


[Linked Image from i.imgur.com]


At one point I was told DOT 3 lasts longer than DOT 4 because it doesn't need the high temp character in it's formula, more anti-corrosives can be delivered. This is somewhat consistent with mfg recommendation, where Euros spec 2yr and others spec none.


Then you're doing it wrong on a VW. If you let it drain dry, you need to use a VCDS to do a proper bleeding process, which involves proper bleeding of the ABS/ESP pump. It is a specific-guided sequence of bleeding and pumping the brakes.
 
Originally Posted by HowAboutThis
My Toyota dealer says every 2.

Dealer recommended services that differ from what the manufacturer say are just extra income for the dealer and more cost to you. Granted, it doesn't hurt your car to do this, just your wallet.
 
I think the general rule of thumb is at least every 5 years in an automobile or truck and every 2 in a motorcycle.
I admit to ALWAYS doing it on my motorcycle but never on my automobiles but that might change.
 
Originally Posted by willbur
Originally Posted by zfasts03
Change it!
I would change it every 2-3 years. 5 years max. Brake fluid is hydroscopic. Especially in humid/moist locations change more frequently.

I use a Mity Vac vacuum extractor and suck it out at the brake caliper bleeders. 1 qt usually does a car, unless it is a Z06 or something with big calipers with two bleeders per caliper. Then get 2 quarts.


Ya know everybody claims brake fluid is hydroscopic, blah blah blah. One guy says it, 1000000 see it, repeat it and another 10000000 etc and becomes a "truth" All internet experts LOL.

A while back Ford engineers visited car recycling yards, took samples of brake fluid from these derelict cars, and what do you know- very little water was found in the brake fluid. So much for hydroscopic. The actual contaminants were leached metals from the brake lines. These contaminants are the bad guys that corrode brake systems. There are available test strips to check for this.


Please provide a link to this Ford study you claim disputes the well founded facts. I would like to read it. It would be very interesting to ask these Ford engineers how their findings directly contradict data from brake fluid manufacturers, and all that is learned from decades of brake system maintenance. Why do you think wet boiling point is one of the most important published measurements for brake fluid? Wet boiling point is one of the measurements that defines if a brake fluid meets DOT3/DOT4 specifications.

http://www.ate-brakes.com/media/3338/ate_td006_dot4-typ200.pdf

You are right about one thing. Brake fluid is not hydroscopic. Rather, it is hygroscopic. Pretty common mistake. It is a little confusing, as the work for lacking an affinity for water is hydrophobic.

https://www.merriam-webster.com/dictionary/hygroscopic
 
Originally Posted by Zolton
Originally Posted by ctechbob
Originally Posted by Zolton
I bleed mine dry, add fluid and close the valves.


Wait, what?


Gravity. Ever heard of it?

[Linked Image from i.imgur.com]


[Linked Image from i.imgur.com]



Yes. It's that force that is pushing your floor jack down into the lawn.
lol.gif
 
Originally Posted by BHopkins
Please provide a link to this Ford study you claim disputes the well founded facts. I would like to read it.
I've "heard" of this before and I think it's just an internet myth or story that someone probably made up and is now being repeated as fact.
 
Originally Posted by BHopkins
Originally Posted by willbur
Originally Posted by zfasts03
Change it!
I would change it every 2-3 years. 5 years max. Brake fluid is hydroscopic. Especially in humid/moist locations change more frequently.

I use a Mity Vac vacuum extractor and suck it out at the brake caliper bleeders. 1 qt usually does a car, unless it is a Z06 or something with big calipers with two bleeders per caliper. Then get 2 quarts.


Ya know everybody claims brake fluid is hydroscopic, blah blah blah. One guy says it, 1000000 see it, repeat it and another 10000000 etc and becomes a "truth" All internet experts LOL.

A while back Ford engineers visited car recycling yards, took samples of brake fluid from these derelict cars, and what do you know- very little water was found in the brake fluid. So much for hydroscopic. The actual contaminants were leached metals from the brake lines. These contaminants are the bad guys that corrode brake systems. There are available test strips to check for this.


Please provide a link to this Ford study you claim disputes the well founded facts. I would like to read it. It would be very interesting to ask these Ford engineers how their findings directly contradict data from brake fluid manufacturers, and all that is learned from decades of brake system maintenance. Why do you think wet boiling point is one of the most important published measurements for brake fluid? Wet boiling point is one of the measurements that defines if a brake fluid meets DOT3/DOT4 specifications.

http://www.ate-brakes.com/media/3338/ate_td006_dot4-typ200.pdf

You are right about one thing. Brake fluid is not hydroscopic. Rather, it is hygroscopic. Pretty common mistake. It is a little confusing, as the work for lacking an affinity for water is hydrophobic.

https://www.merriam-webster.com/dictionary/hygroscopic



Google it. I did this several years ago bc this subject keeps on coming up ( and up and up...). I'll try again. See what happens

Ok- a very quick search found this from Phoenix Brake Systems FAQ section. Its not the original source. I'll keep looking

"Q: What about moisture in brake fluid?
Interestingly, moisture is not the main contaminant that causes brake system problems, though thought to be the main problem by many industry professionals. Research by the Ford Motor Company indicates moisture contamination of brake fluid was approximately 1% in test vehicles that had been in service as long as 7 years. Moisture testing is recommended only for severe-duty vehicles."
 
Last edited:
Originally Posted by hallstevenson
Originally Posted by HowAboutThis
My Toyota dealer says every 2.

Dealer recommended services that differ from what the manufacturer say are just extra income for the dealer and more cost to you. Granted, it doesn't hurt your car to do this, just your wallet.



I don't think my Toyota maintenance booklet even mentions brake fluid flush. Every 2-4 years is what I'll do, however. Because it's what I've done on every car I've ever owned. Tires, brakes, steering. Three things I don't neglect. The dealer I use doesn't push stupid things. Even sitting in the waiting room I've never heard them offer or recommend something silly to anyone. TGMO synthetic oil change, tire rotation, full report on brake thickness, tread depth, car wash, vacuum the interior for $60. I take the dog for a 45 minute walk and the car is done. Pretty easy choice.
 
Originally Posted by willbur
Originally Posted by BHopkins
Originally Posted by willbur
Originally Posted by zfasts03
Change it!
I would change it every 2-3 years. 5 years max. Brake fluid is hydroscopic. Especially in humid/moist locations change more frequently.

I use a Mity Vac vacuum extractor and suck it out at the brake caliper bleeders. 1 qt usually does a car, unless it is a Z06 or something with big calipers with two bleeders per caliper. Then get 2 quarts.


Ya know everybody claims brake fluid is hydroscopic, blah blah blah. One guy says it, 1000000 see it, repeat it and another 10000000 etc and becomes a "truth" All internet experts LOL.

A while back Ford engineers visited car recycling yards, took samples of brake fluid from these derelict cars, and what do you know- very little water was found in the brake fluid. So much for hydroscopic. The actual contaminants were leached metals from the brake lines. These contaminants are the bad guys that corrode brake systems. There are available test strips to check for this.


Please provide a link to this Ford study you claim disputes the well founded facts. I would like to read it. It would be very interesting to ask these Ford engineers how their findings directly contradict data from brake fluid manufacturers, and all that is learned from decades of brake system maintenance. Why do you think wet boiling point is one of the most important published measurements for brake fluid? Wet boiling point is one of the measurements that defines if a brake fluid meets DOT3/DOT4 specifications.

http://www.ate-brakes.com/media/3338/ate_td006_dot4-typ200.pdf

You are right about one thing. Brake fluid is not hydroscopic. Rather, it is hygroscopic. Pretty common mistake. It is a little confusing, as the work for lacking an affinity for water is hydrophobic.

https://www.merriam-webster.com/dictionary/hygroscopic



Google it. I did this several years ago bc this subject keeps on coming up ( and up and up...). I'll try again. See what happens

Ok- a very quick search found this from Phoenix Brake Systems FAQ section. Its not the original source. I'll keep looking

"Q: What about moisture in brake fluid?
Interestingly, moisture is not the main contaminant that causes brake system problems, though thought to be the main problem by many industry professionals. Research by the Ford Motor Company indicates moisture contamination of brake fluid was approximately 1% in test vehicles that had been in service as long as 7 years. Moisture testing is recommended only for severe-duty vehicles."



I cant find the original source. I'll contact Phoenix and maybe they will provide it. Regarding wet boiling point, it is calculated using 4% moisture.
 
A Google search reveals it isn't the presence of water so much as the anti-corrosion properties of the brake fluid that get depleted.

I'm not sure I buy that. After anti-corrosion properties are depleted, then what IS the corrosion mechanism?
 
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