Outer Limits 4x4 Board

since my rodeo was serviced at the stealership for its 40000km service I dont know what brake fluid they put in it ie dot3 or dot4. So can the two be mixed or do i have to drain the whole system to put more brake fluid in without knowing what is in there.
The car was serviced only 5000km ago so the fluid does not need draining just topped up a little
thanks

msg wrote:since my rodeo was serviced at the stealership for its 40000km service I dont know what brake fluid they put in it ie dot3 or dot4. So can the two be mixed or do i have to drain the whole system to put more brake fluid in without knowing what is in there.
The car was serviced only 5000km ago so the fluid does not need draining just topped up a little
thanks

why dont you just ask them, im sure they will tell you

Until the guy behind the counter at the service department reads the sign above the front door that says "SERVICE" and realises that he is there to provide some sort of service we wont be going back there until hell freeses over.
Rant and winge over. Now back to the first post, Is there any problem with mixing different brake fluids
thanks

DOT 3 and DOT 4 are mixable without problems. The only exception is DOT 5 silicone which is extremely rare.
DOT 5.1 is a super DOT 4 and shouldn't be confused with DOT 5 silicone.

KiwiBacon wrote:DOT 3 and DOT 4 are mixable without problems. The only exception is DOT 5 silicone which is extremely rare.
DOT 5.1 is a super DOT 4 and shouldn't be confused with DOT 5 silicone.

I have read that DOT4 shouldnt be used in Toyotas despite being theoretically interchangeable. I cant remember why, I think it may have something to do with seals??

Stick to whatever is specified by the manufacturer.

80's_delirious wrote:

KiwiBacon wrote:DOT 3 and DOT 4 are mixable without problems. The only exception is DOT 5 silicone which is extremely rare.
DOT 5.1 is a super DOT 4 and shouldn't be confused with DOT 5 silicone.

I have read that DOT4 shouldnt be used in Toyotas despite being theoretically interchangeable. I cant remember why, I think it may have something to do with seals??

Stick to whatever is specified by the manufacturer.

toyota hasnt officially supported dot 4, but it is used in toyotas by alot of mechanics (and myself)

they probably just used cordial

The wrong brake fluid other than specifies stuff can damage seals.

Some model Toyotas had ( expensive ) seal issues with DOT4 fluid instead of DOT3 - so its always possible that you might be unlucky.

You do sometimes see "DOT4 can be used if DOT3 isn't available" in vehicle manuals but wether its a completely acceptable option or not never seems to be answered. I've asked a number of manufacturers directly and got the " can be used if... " line without any technical explanation as to pro's and cons.

On paper the higher boiling point / less moisture sensitive fluids are to be prefered BUT there are enough real compatibility questions to make using whats recomended my choice.

And.... there's a lot of BS floating around about Brake Fluids - i'd suggest a cautious approach unless you can get DEFINATE advice from a manufacturer.

Yes, just buy new bottle of castrol etc dot 4.

Bazzle

MightyMouse wrote:Some model Toyotas had ( expensive ) seal issues with DOT4 fluid instead of DOT3 - so its always possible that you might be unlucky.

You do sometimes see "DOT4 can be used if DOT3 isn't available" in vehicle manuals but wether its a completely acceptable option or not never seems to be answered. I've asked a number of manufacturers directly and got the " can be used if... " line without any technical explanation as to pro's and cons.

On paper the higher boiling point / less moisture sensitive fluids are to be prefered BUT there are enough real compatibility questions to make using whats recomended my choice.

And.... there's a lot of BS floating around about Brake Fluids - i'd suggest a cautious approach unless you can get DEFINATE advice from a manufacturer.

How about the code that DOT fluids have to meet?
http://www.nhtsa.dot.gov/staticfiles/DO ... 116-04.pdf

Cuts straight through all the BS. Including each manufacturers "we are the best" crap.

I found this surprising about Toyota too.

It came up in this thread: http://www.outerlimits4x4.com/ftopic169 ... =fluid+dot

Anyway DJ_Hansen posted this:



Make of it what you will!

So we've got one MC failure where toyota got out of the warranty because the fluid used didn't match their description?

msg wrote:Until the guy behind the counter at the service department reads the sign above the front door that says "SERVICE" and realises that he is there to provide some sort of service we wont be going back there until hell freeses over.
Rant and winge over. Now back to the first post, Is there any problem with mixing different brake fluids
thanks

Then ring them and ask what they use..

If your unsure, bleed the system. takes about 30-45mins.

KiwiBacon wrote:So we've got one MC failure where toyota got out of the warranty because the fluid used didn't match their description?

Apparently.

I always use DOT 4, personally.

KiwiBacon - your stretcing my brake fluid knowledge a bit... but if I understand it correctly the DOT spec details the operational performance ( temp, water tolerance etc etc ) of the fluid not its chemical composition.

Some fluids don't like some seal materials so it may be "compatible" from a performance point of view but not acceptable from a seal material perspective. So DOT4 is backwards compatible from a performance view with DOT3 but chemically......... ? It just gets harder.....


Still i've been wrong enough times before so........

MightyMouse wrote:KiwiBacon - your stretcing my brake fluid knowledge a bit... but if I understand it correctly the DOT spec details the operational performance ( temp, water tolerance etc etc ) of the fluid not its chemical composition.

Some fluids don't like some seal materials so it may be "compatible" from a performance point of view but not acceptable from a seal material perspective. So DOT4 is backwards compatible from a performance view with DOT3 but chemically......... ? It just gets harder.....


Still i've been wrong enough times before so........

Have a read of that PDF I linked up. It's a great insomnia cure and will answer everything you never needed to know.

Basically the DOT standards include all the compatibility tests for all the expected materials. The biggest difference between different DOT numbers is the heat range (i.e. minimum boiling points).

My mate works as a mechanic at a toyota dealership, on 2 occasions he has had to replace every seal in the braking system on 100 series cruisers, believed to be caused by using DOT4.

Which year models exactly i couldnt tell you (tho i can ask) but when i had my 105 he made it pretty clear to use DOT3.

To the original poster - Check the cap of the brake fluid, it will tell you what is reccomended. (doesnt mean the mech used that). Also why is the fluid low, does it have a leak? or did the mechanic just not fill it up?

My 2005 78 Series Troopy has clearly printed on the top of the brake and clutch reserve tanks covers - use only DOT3 ...

Bugger me I did not realise there was an issue with DOT4 - and that is what I replaced it with!!!
Interesting as I noticed a different noise from the clutch peddle, bit of a rubber type of squeak!
Sounds like I need to drain it and replace it all with DOT3 Fluid... soon!
Who said you never learn anything from forums... not me

Thanks KiwiBacon... lost a few more minutes of my life skimming it.

i didn't find any real data covering compatibility of fluids to seals... or specify chemistry. Fluid performance yes - system compatibility ?

Thanks KiwiBacon... lost a few more minutes of my life skimming it.

i didn't find any real data covering compatibility of fluids to seals... or specify chemistry. Fluid performance yes - system compatibility ?

MightyMouse wrote:Thanks KiwiBacon... lost a few more minutes of my life skimming it.

i didn't find any real data covering compatibility of fluids to seals... or specify chemistry. Fluid performance yes - system compatibility ?

That's the interesting part. There's nothing in the standard which suggests that DOT 4 or 5.1 will be incompatible with a DOT 3 system.

Just checked my work car (used jap import nissan) and it says DOT3 only. It's running DOT4. I think my brother subaru (also used jap import) says DOT3 only too.

When you look closely at the standards all the fluid compatibility is chehcked against "standard" rubbers. It would also seem that in reality this rubber is only one of many used in seals by manufacturers.

Had a quick read of some Bosch info and it also made frequent references to the incompatibility issues of differing seal materials with DOT ratings.

Makes the rebuild issue very interesting..... originally used material X which was compatible with fluid y but now uses material Z so its now compatible with ???

I wonder if there are also issues with seals that have been exposed to one DOT variety and are then exposed to another. As in, material X might be fine with either DOT 3 or DOT 4, but is not fine with DOT 4 after it has been soaking in DOT 3 for ten years. Just wondering.

chimpboy wrote:I wonder if there are also issues with seals that have been exposed to one DOT variety and are then exposed to another. As in, material X might be fine with either DOT 3 or DOT 4, but is not fine with DOT 4 after it has been soaking in DOT 3 for ten years. Just wondering.

like the old argument of mineral vs synthetic oils in engines and having old seals start to leak...

chimpboy wrote:I wonder if there are also issues with seals that have been exposed to one DOT variety and are then exposed to another. As in, material X might be fine with either DOT 3 or DOT 4, but is not fine with DOT 4 after it has been soaking in DOT 3 for ten years. Just wondering.

thats a possibility

Castrol Response DOT4 lists on the back that it is compatible with ALL Systems that sipulate DOT3 and DOT4.

So I guess if it lunches your MC, you can ring castrol and ask them to cough up?

hokey wrote:they probably just used cordial

http://www.outerlimits4x4.com/ftopic33763.php

Well at least with cordial you KNOW what's going to happen.

MightyMouse wrote:Well at least with cordial you KNOW what's going to happen.

Very fitting sig line

My dad and I are about to do our brake fluid in our 100 series cruisers. (im doing my diffs, transfer, auto, wheel bearings, etc aswell).

And with this thread popping up he did a bit of investigating.

He works with an ex toyota mechanic and asked him about it, He said dot 4 and dot 3 are fine to use. "JUST DONT USE DOT 5!!!"

He also asked a friend of his who has put 200thousand on his 03 100series and is a qualified mechanic, and he said the same thing, he uses dot 4(has since he baught it at 50,000k's, now has 250,000k's) "DONT USE DOT 5!!!"

So then he rang toyota and they said "we only recomend toyota's dot 3 brake fluid for use in the 100 series landcruiser" (expected).

Also, Castrol list on thier DOT4 brake fluid that it is suitable for use in all cars that specify DOT3 and DOT4 brake fluids.

And also all the research i have done on the net indicates DOT4 is just a superior heat range version of DOT3 and can be used in place of eachother, so today I baiught 2 x 5litre Castrol Response Dot 4, And we will change our fluid this weekend.

Should the vehicles burst into flames as soon as we pour the DOT 4 into the reservoir, I will jump straight online and let you guys know (pictures included of course).