Brake Fluid Specifications and Information

[Kingsize]

First off the ONLY brake fluids that should be used in the brake and clutch systems of the GTO are of hygroscopic mineral properties, mainly polyethylene glycol, DOT 3, 4, & 5.1

DO NOT use DOT 5 specification as it is a hydrophobic silicone based fluid that will not work properly with ABS systems and will cause the seals in your GTO to fail.

GM specifies DOT 4 brake fluid in our braking and clutch systems. While I would never downgrade to a DOT 3, there are some reasons someone my want to use specification DOT 5.1, such as in road or drag racing where the driver heavily relies on the clutch and braking systems.

In the United States, all brake fluids must meet Standard No. 116; Motor vehicle brake fluids. Under this standard there are three Department of Transportation (DOT) minimal specifications for brake fluid. They are DOT 3, 4, & 5.1. One of the important characteristics of brake fluid is its boiling point. Hydraulic Brake and clutch systems rely on an incompressible fluid to transmit force. Liquids are generally incompressible while gases are compressible. If the brake fluid boils (becomes a gas), it will lose most of its ability to transmit force. This may partially or completely disable the brakes and or clutch system. Usually the only time you are likely to boil your brake fluid or clutch fluid is during a period of prolonged and/or frequent use. The use of a higher specification will allow longer and more frequent use of the braking or clutch system without reaching the boiling point and feeling "spongy", 5.1 being the highest specification. Also note that since this fluid is hygroscopic it absorbs water readily. As brake fluid absorbs water, its boiling point decreases. It can absorb water from the air, which is why you should avoid opening your car's brake fluid reservoir very often. For the same reason, you should always keep containers of brake fluid tightly sealed if kept for short periods of time. It is my personal opinion that if containers have been open for over 1 month they should be properly disposed of as odds are they have been contaminated. As a general rule, brake fluids with different DOT ratings should not be mixed. Although all DOT fluid is compatible, (this is part of the DOT specification) it will dilute and reduce the properties of the higher specification DOT fluid thus rendering your extra $ useless. If you do switch to DOT 5.1 be sure and do a complete flush of the system using that specification fluid.

[gtohmy]

I thought I would post this information up as I have researched this in the past and posted it elsewhere.
Keep in mind a few things. 1. there is no set standard for the manufactures listing there "temps". You pretty much have to take the information they are providing on faith. 2. The prices I have were found on the internet as lowest with a minimal amount of searching. They don't take into account shipping/handling and how that might add to the price. 3. i have sorted by dry temp highest to lowest. 4. There are some relative bargains to be had if you look at the temps vs. price per ounce.

brand ~dot rating ~dry boiling ~wet boiling ~price per bottle ~price per ounce
wilwood exp600 plus ~dot 4 ~626 ~417 ~18.95/16.9oz ~1.12
Neo Super Dot 16 ~dot 4 ~610 ~421 ~18.95/16 oz ~1.18
ap prf racing 660 ~dot 4 ~608 ~311 ~29.95/16.9oz ~1.77
bremboLCF 600+ ~dot 4 ~601 ~399 ~19.95 1/2 liter ~1.18
Motul RBF 600 ~dot 4 ~594 ~421 ~17.95/16.9oz ~1.06
ap racing 600 ~dot 3 ~590 ~410 ~18.00/16.9 oz ~1.07
castrol SRF ~dot 4 ~590 ~518 ~74.95 liter ~2.22
amsoil series 600 ~dot 4 ~580 ~410 ~10.40/12oz ~0.87
Pentosin racing brake ~dot 5.1 ~572 ~392 ~22.00 liter ~0.65
wilwood hi-Temp 570 ~dot 3 ~570 ~284 ~5.95/12 oz ~0.50
FordHD ~dot 3 ~550 ~284 ~6.00 liter ~0.18
Performance Friction Z ~dot 3 ~550 ~284 ~10.00/16oz ~0.63
ate super blue ~dot 4 ~536 ~396 ~9.95 liter ~0.29
ate super 200 ~dot 4 ~536 ~396 ~9.95 liter ~0.29
ap racing 551 ~dot 3 ~527 ~302 ~12.50/16.9 oz ~0.74
amsoil series 500 ~dot 3 ~525 ~313 ~4.90/12 oz ~0.41
brembo evo 500++ ~dot 4 ~520 ~336 ~12.95 1/2 liter ~0.77
Gunk/Berryman HD ~dot 4 ~510 ~311 ~2.50/12 oz ~0.21
Motul Dot 5.1 ~dot 5.1 ~509 ~365 ~7.95/16.9oz ~0.47
prestone syn dot 4 ~dot 4 ~500 ~311 ~3.50/12 oz ~0.29
Pentosin super Dot 4 ~dot 4 ~500 ~338 ~10.95/33oz ~0.33
catrol gt lma ~dot 4 ~446 ~311 ~2.95/12 oz ~0.25

[dkrowner]

i use Motul 5.1 DOT in the gto & gsxr1000k6 in swear by it

[MuhThugga]

I've got ATE Super Blue in the GTO's clutch.

Still need to change out the brake fluid.

[afgun]

Any retail vendors of ATE (specially in the Austin area) ?

[1MtnGoat]

If you can't find it locally you can order from bavauto.com they sell both blue and gold.

[BillsMafia]

good stuff

[afgun]

Thanks; got some from stang2goat. Will order some more for top-offs tho... Tye is doing brakes soon (at my place) so mebbe I'll just ask him to get some for me with his order.

[littlecrunch2000]

Originally Posted by afgun

Thanks; got some from stang2goat. Will order some more for top-offs tho... Tye is doing brakes soon (at my place) so mebbe I'll just ask him to get some for me with his order.

I might try and get in on this order. I wonder if there would be any type of discount for a bigger order. Get with Tye and see what he can do as I am curious about this as well.

[Poolshark1321]

I am having a little trouble finding definitive proof that it is ok to use DOT 5.1 brake fluid in our clutch system. Some people say its ok... other say its a no no...

From what I have read it seems as though its the latest greatest and theres nothing wrong with using it in the clutch system unlike the DOT 5 that is bad for our clutch system.

Thx...

[afgun]

From what I understand, DOT 3, 4 and 5.1 are all compatible fluids... but be sure to do your own research; that said, why go to the extra expense of 5.1 over DOT 4 for the clutch? Does yours get that hot that you need the extra protection?

[Poolshark1321]

Originally Posted by afgun

From what I understand, DOT 3, 4 and 5.1 are all compatible fluids... but be sure to do your own research; that said, why go to the extra expense of 5.1 over DOT 4 for the clutch? Does yours get that hot that you need the extra protection?

Currently I am still on the stock clutch assembly and clutch lines...

I do notice on any WOT pulls that my clutch pedal gets insanely mushy and wont come all the way back up to the top. Im sure just replacing the clutch fluid with DOT 4 would solve this.

The way I look at though is... If I am going to do it, I am going to do it right and with the best possible product that I can find. If that means DOT 5.1 is slightly better on the temp side of things... I am going to do it. I will be hitting up the track pretty often once I pick up my 15" BMW wheels, MT's, SS clutch lines and a helmet.

Kingsize knows what hes talking about so I will probably grab some DOT 5.1 and never look back... the only reason I asked specifically about the clutch was because this was aimed more toward the breaks.

[HeyGuiher]

The OEM brake and clutch fluid Is DOT 5.1
Depending on the company "Super" DOT4 is the same as 5.1 meaning that our cars are actually 5.1 spec.