2-year brake fluid change

Jor-el · January 24, 2017

So my 09' Lancer CS3 had its last brake fluid change in 2014. Mitsubishi recommends changing brake fluid every 2 years with DOT 3 or DOT 4 brake fluid.

Q 01: I've run less than 12k kms during this time period. Is it a good idea to change brake fluid nonetheless?

Q 02: I don't remember which brake fluid is in the system now, DOT 3 or DOT 4. Does it matter which fluid is in there when getting a complete brake fluid flush?

Q 03: Which fluid do you guys recommend, DOT 3 or DOT 4?

Kavvz · January 24, 2017

On 1/24/2017 at 1:22 PM, Jor-el said:

So my 09' Lancer CS3 had its last brake fluid change in 2014. Mitsubishi recommends changing brake fluid every 2 years with DOT 3 or DOT 4 brake fluid.

Q 01: I've run less than 12k kms during this time period. Is it a good idea to change brake fluid nonetheless?

Q 02: I don't remember which brake fluid is in the system now, DOT 3 or DOT 4. Does it matter which fluid is in there when getting a complete brake fluid flush?

Q 03: Which fluid do you guys recommend, DOT 3 or DOT 4?

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Google says: "Dot 3, 4, and 5.1 are glycol ether based. They are compatible, but like motor oils, you should use the recommended or higher grade fluid. Dot 4 and 5.1 also have borate ester to handle higher temperatures. DOT 3, 4, and 5.1 fluids are found in mostbrake and clutch systems."

So to answer your question thanks to the google Gods I would confidently say like I knew all along: It doesn't matter flush, and go with DOT 4

(Oh and this I do know the answer to: Brake Fluids and motor oil break down and lose their composition over time so you should change the brake fluid regardless of the amount of KM you've run)

Edited January 24, 2017 by Kavvz

Davy · January 24, 2017

During a brake fluid flush, the new brake fluid is added, and the system is bled until the old fluid is flushed out of the system together with a bit of new fluid as well. So you don't have to worry about them mixing. Besides, DOT3 and DOT4 can be safely mixed and I'm sure it doesn't cause any damage to the system.

Kavvz · January 24, 2017

On 1/24/2017 at 3:58 PM, Jor-el said:

Thanks K, but what if I already have DOT 3 in the system? I read somewhere Mixing DOT 4 with DOT 3 leads to corrosion. Is there a way to get rid of existing oil completely before filling up new brake fluid?

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Yeap, I've heard that as well; but according to google that's an old wive's tale and they are compatible to mix (DOT 4 and 3 that is, the TDi forum swears that 5 and 4 should not be mixed). Also as our pal Davy says, during a flush almost all the old brake fluid gets pumped out and then bleed out so very little of the old stuff remains.

As you're at the 2 year limit you'll have to do a flush (pump the old stuff out and bleed the brakes) and once you do that, if you go with DOT 4 you should sitting pretty.

However, if shit goes down, and all hell breaks loose (pun intended) I take absolutely NO responsibility as all this was presumed mostly on what I read off google....I kid, I kid! I've mixed DOT 3 and 4 when I had the Mazda, as I was too cheap to do a proper flush. I just drained out the the old brake fluid and refilled it up with DOT 4, and it was fine. (In my defense: I'm not sure what happens at the agents but this is what most smaller, under the mango tree places do anyway.) With a proper flush you should have nothing to worry about.

Edited January 25, 2017 by Kavvz

Twin Turbo · January 25, 2017

Your statement says what to do, just do it.

use one type of fluid throughout the life of your car and manke it a good one as you'll prob , need to top up inbetween changes for br pad changes etc.

Brake fluiid absorbs moisture from the air and therefore looses efficiency of brakes and must be changed periodically for safety.

Edited January 25, 2017 by Twin Turbo

Twin Turbo · January 25, 2017

On 1/25/2017 at 5:45 AM, Jor-el said:

@Kavvz @Davy @Twin Turbo Thanks guys, will get it done then... decided to get DOT 4 filled up and stick to it.

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Cheers,.!

Jor-el · January 24, 2017

On 1/24/2017 at 2:44 PM, Kavvz said:

Google says: "Dot 3, 4, and 5.1 are glycol ether based. They are compatible, but like motor oils, you should use the recommended or higher grade fluid. Dot 4 and 5.1 also have borate ester to handle higher temperatures. DOT 3, 4, and 5.1 fluids are found in mostbrake and clutch systems."

So to answer your question thanks to the google Gods I would confidently say like I knew all along: It doesn't matter flush, and go with DOT 4

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Thanks K, but what if I already have DOT 3 in the system? I read somewhere Mixing DOT 4 with DOT 3 leads to corrosion. Is there a way to get rid of existing oil completely before filling up new brake fluid?

Jor-el · January 25, 2017

@Kavvz @Davy @Twin Turbo Thanks guys, will get it done then... decided to get DOT 4 filled up and stick to it.

Jor-el · January 25, 2017

Found an interesting article on brake fluid ratings... Appearantly DOT 4 degrades faster than DOT 3 over time.

* * *

DOT 3 fluids are usually glycol ether based, but as stated earlier, that is not because they are required to be. The brake fluid industry has determined by consensus that glycol ether fluids are the most economical way to meet the requirements.

By definition, DOT 3 fluids must have a minimum dry boiling point (measured with 0 percent water by volume) of 401°F and a minimum wet boiling point (measured with 3.7 percent water by volume) of 284°F. The specification says little more as far as the performance enthusiast is concerned.

DOT 4 fluids are also glycol ether based, but have a measure of borate esters added for improved properties including increased dry and wet boiling points. A seldom talked about characteristic is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. By FMVSS116 standards, DOT 4 fluids must have a minimum dry boiling point of 446°F and a minimum wet boiling point of 311°F.

DOT 4 is the grade applicable to most race engineered brake fluid in the world today, especially with regard to viscosity limit. Note that although the DOT 4 designation has a minimum dry and wet boiling point, a DOT 4 racing brake fluid may have a dry boiling point over 600F. Its viscosity is challenged, however, to be under the viscosity limit of 1,800 mm2/sec. Some claimed racing brake fluids exceed this important limit. Caution should be exercised if these fluids are used in race cars with ABS systems. This does not mean that DOT 4 fluids are necessarily better than DOT 3 fluids. Remember, the boiling points listed are minimums. There are certain DOT 3 fluids with higher boiling points than some DOT 4 fluids. The real differentiating factor is that DOT 4 fluid should be changed more often than a DOT 3 fluid, because of the effects and rates of water absorption.

* * *

http://stoptech.com/technical-support/technical-white-papers/brake-fluid

Kavvz · January 26, 2017

On 1/25/2017 at 6:47 AM, Jor-el said:

Found an interesting article on brake fluid ratings... Appearantly DOT 4 degrades faster than DOT 3 over time.

* * *

DOT 3 fluids are usually glycol ether based, but as stated earlier, that is not because they are required to be. The brake fluid industry has determined by consensus that glycol ether fluids are the most economical way to meet the requirements.

By definition, DOT 3 fluids must have a minimum dry boiling point (measured with 0 percent water by volume) of 401°F and a minimum wet boiling point (measured with 3.7 percent water by volume) of 284°F. The specification says little more as far as the performance enthusiast is concerned.

DOT 4 fluids are also glycol ether based, but have a measure of borate esters added for improved properties including increased dry and wet boiling points. A seldom talked about characteristic is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. By FMVSS116 standards, DOT 4 fluids must have a minimum dry boiling point of 446°F and a minimum wet boiling point of 311°F.

DOT 4 is the grade applicable to most race engineered brake fluid in the world today, especially with regard to viscosity limit. Note that although the DOT 4 designation has a minimum dry and wet boiling point, a DOT 4 racing brake fluid may have a dry boiling point over 600F. Its viscosity is challenged, however, to be under the viscosity limit of 1,800 mm2/sec. Some claimed racing brake fluids exceed this important limit. Caution should be exercised if these fluids are used in race cars with ABS systems. This does not mean that DOT 4 fluids are necessarily better than DOT 3 fluids. Remember, the boiling points listed are minimums. There are certain DOT 3 fluids with higher boiling points than some DOT 4 fluids. The real differentiating factor is that DOT 4 fluid should be changed more often than a DOT 3 fluid, because of the effects and rates of water absorption.

* * *

http://stoptech.com/technical-support/technical-white-papers/brake-fluid

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Very cool read- Thanks for sharing!

nagaya · February 18, 2017

As I remember I have never changed brake oil in my '12 CS3 even at the 40000km service at U**** M****, they even haven't done it, Car is now at 45000km, Please advice.

Twin Turbo · February 18, 2017

Better late than never, so change it

Davy · February 18, 2017

On 2/18/2017 at 1:12 AM, nagaya said:

As I remember I have never changed brake oil in my '12 CS3 even at the 40000km service at U**** M****, they even haven't done it, Car is now at 45000km, Please advice.

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What sort of advice are you looking for? Isn't the answer obvious? :rolleyes:

Jor-el · February 18, 2017

On 2/18/2017 at 1:12 AM, nagaya said:

As I remember I have never changed brake oil in my '12 CS3 even at the 40000km service at U**** M****, they even haven't done it, Car is now at 45000km, Please advice.

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5 year old brake fluid? it would be great if you could get a moisture check done before changing the brake fluid and share... UM workshop ought to have the necessary equipment, provided a moisture checker costs less than $10 on eBay. I ordered one but it would take at least a month to be delivered

Didn't you get the service booklet that comes with the car? It says brake fluid change is recommended every 2 years.

I didn't have time to get it done yet, will deffa get it done within this month

Edited February 18, 2017 by Jor-el