Brake Fluid DOT3

[LibertyTC]

I was surprised to see DOT3 recommended in manual for brake fluid in the KJ. (lowest boiling point) I thought ABS would have used something better like DOT4.(popcorn)
I guess now a days there are brake fluid test strips (not that I can find them) and had a flush done a year ago, but still am going to suck out the reservoir and put some fresh DOT3 in.(mud)
I just called the dealer they said 4 is better...ya ok (higher boiling point) i guess brake fluid is mixable 3 with 4?
Note: After I removed the Fluid from reservoir, the bottom of the tank was black, carbon type particles. Yuk.
Filled it again with "Gunk" DOT 3 LOL.

 

[BigRich201]

abs uses DOT 3 non abs uses DOT 4. DOT 3 and 4 are mixable and wont harm your system

 

[trail rated]

abs uses DOT 3 non abs uses DOT 4. DOT 3 and 4 are mixable and wont harm your system

Huh? My KJ doesn't have ABS and it says to use DOT 3.

To the OP: Apparently you can use DOT 4 in your braking system if you would like, DOT 5.1 is also mixable with DOT 3 & 4. However, you should NEVER mix DOT 5 with DOT 4, 5, and 5.1.

 

[kb0nly]

Mine uses ATF+4

Just kidding.. (lol)

Well it seems like everything under there is this fluid, i'm surprised someone hasn't put it in by accident yet.

Power Steering
Trans
Transfer Case

All i need is a gallon of ATF+4 and i got reserve for three different things.

 

[kb0nly]

I haven't had to top off the brakes yet, so i will have to dig out my manual and see what it says on this.

 

[LibertyTC]

It will Say..

I haven't had to top off the brakes yet, so i will have to dig out my manual and see what it says on this.

It will say DOT3. If that oil has been in there for a while and you have not flushed it, better suction the old stuff out. Mine had a flush 1 year ago and the bottom of my reservoir looked really dirty and so was the brake oil. Amazing how much crud is in the brake lines/system.
Filler er up with clean brake oil every once in a while!

 

[tjkj2002]

Never ever "TOP OFF" your master cylinder,and why?

When your front and rear brakes are brand new the master cylinder level should be at the max mark(no heat expansion with brake fluid) and when the level drops close to or at the min level you need F/R brakes.Your fluid level is a indication of brake wear,plus if you top it off when you change your brakes you can end up with a overfilled master cylinder or a really big mess and brake fluid does a real good job at stripping paint off of anything.You should never need to add brake fluid to your master cylinder unless you have a leak or flushing/bleeding the system.

As far as DOT 3 and 4 basically the only difference is boiling points,under normal conditions and care you will never need anything over a DOT 3 fluid.If you wheel changing out to DOT 4 is a good idea.And yes they are 100% mixable with each other and no harm will be done.Do not add DOT 5 brake fluid,you will ruin your braking system because DOT 5 is silicone brake fluid and special parts are needed to use DOT 5.DOT 5.1 brake fluid is okay to mix with DOT 3/4 but DOT 5.1 is rather expensive and many for race apps.

 

[kb0nly]

You should keep the brake fluid at the level on the reservoir as the brakes wear, however if the wear indicators on your brake pads are hitting the rotor thats a whole other thing, yes then its time for replacement. But i have seen plenty of vehicles with the fluid at the MIN mark and the pads still got plenty of life left.

It is amazing how much crud builds up in the brake fluid considering its a sealed system, or should be a sealed hydraulic system.

I plan on suctioning mine out and refilling the reservoir one of these days, it does look like its getting dirty.

 

[LibertyTC]

What about cleaning the reservoir?

Hey TjKJ- Good points for sure...I refilled to the same level it was before, to see when brakes were needed.
Question: Due to the amount of black dirt sitting on the bottom,(blarg) is there a simple way to remove the reservoir for cleaning?

 

[tjkj2002]

Question: Due to the amount of black dirt sitting on the bottom,(blarg) is there a simple way to remove the reservoir for cleaning?

There sure is but the whole master cylinder has to come off as a unit and do not separate,then you will have to bench bleed the master before installing and if you have ABS it's a trip to the dealership to get the ABS pump bleed.

 

[BigRich201]

Huh? My KJ doesn't have ABS and it says to use DOT 3.

To the OP: Apparently you can use DOT 4 in your braking system if you would like, DOT 5.1 is also mixable with DOT 3 & 4. However, you should NEVER mix DOT 5 with DOT 4, 5, and 5.1.

thats generally the rule of thumb but the kj is of course excluded from that rule.

 

[Redbone]

5.1 FTW. It doesn't absorb water as bad as the others. Don't be concerned about using 4 or 5.1 when 3 is in the manual. The only difference is boiling point. 3 is good enough. I use only 5.1 because of water absorption. The crap in the bowl and lines is from water causing corrosion.

NEVER leave the bowl or container of fluid open. Brake fluid absorbs water readily.

BTW brake fluid is NOT an oil.
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VAPOLUTION ACCESSORIES

 

[Boiler]

5.1 FTW. It doesn't absorb water as bad as the others. Don't be concerned about using 4 or 5.1 when 3 is in the manual. The only difference is boiling point. 3 is good enough. I use only 5.1 because of water absorption. The crap in the bowl and lines is from water causing corrosion.

NEVER leave the bowl or container of fluid open. Brake fluid absorbs water readily.

BTW brake fluid is NOT an oil.

We have a lift truck that we sell to the state of alaska that has a cold weather package. Included is a flush of the original brake fluid with another fluid with a lower pour point. I think it is 5.1 because I distinctly remember the whole water absorption benefit. That should keep fluid from giving you the spongy brake pedal as well as limiting corrosion shouldn't it?

 

[Auberon]

Bleeding brakes/fluid

With all my vehicles, I pressure bleed (so it takes no time) every vehicle every 6 months as this stuff is so hygroscopic (some say hydroscopic) but it likes water!!!
The alternate is sleeving all master cylinders, slave cylinders with stainless to avoid corrosion / temp effects.
The only time you want water in barakes is in a complete trail failure & you have to do an emergency fix for as short a time as possible. I'm sure I'll be shot down for this one but if your stuck 2000 miles from nowhere & water will get you home, it is doable. Replace with as much rated brake fluid ASAP then do a full system clean ASAP.
Remember water won't wreck your seals - the wrong petrochemical will.

Please use the DOT rating your book says to use.
Cheers
Auberon

 

[Auberon]

Black gunk

Submit this wud be rubber from overheating + friction + hardening seals/cups caused by the presence of water (yuck).
Yes they are mixable (with residues in lines only) but there are protocols:
*mixing...limited
*unopened containers etc. unless you are in a position to vacuum seal your containers (depending on how big they are).

On a different note:The tough thing is that water & brake fluid are miscible.

Yes I am fanatical about engineering it right - you bet! and have been told I am too particular . No matter.
Too old to change to short cut ways now - experience has taught there is a better and not so good way in most cases but ........ALWAYS OPEN TO LEARNING A BETTER WAY. (Not talking 'bout trail rescues).

Auberon

 

[tjkj2002]

Actually water absorption has been proven to not be as much as a problem as once thought since most newer vehicles use aluminum brake lines,aluminum master cylinders,and aluminum calipers.Those test strips that shops use does not measure water content but copper content which is a better test for bad brake fluid.

 

[tjkj2002]

thats generally the rule of thumb but the kj is of course excluded from that rule.

No it is not,the KJ's braking system is no different then any other newer vehicles.

 

[Redbone]

Originally Posted by BigRich201
thats generally the rule of thumb but the kj is of course excluded from that rule.

No it is not,the KJ's braking system is no different then any other newer vehicles.

Yeah, I kinda wondered about that statement myself.headscratch.gif
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Coach purses

 

[BigRich201]

from what i learned dot 4 is supposed to be used with non abs because during hard braking the brakes arent pulsating so its gonna build up more heat than abs

 

[Redbone]

So if it calls for DOT 4 a person has to use DOT 4 at a minimum. If the manual calls for DOT 3 A PERSON should use DOT 3 as a minimum but can upgrade to DOT 4. In both cases a person can upgrade to 5.1. That tells me KJs are like every other vehicle on the road ...... except for those using DOT 5.
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Half-Baked