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CrazyAzn · 08-15-2006, 08:33 PM

well a friend of mine sent me this:

a former materials engineering supervisor at a major automotive brake system supplier, I feel both qualified and obligated to inject some material science facts into the murky debate about DOT 5 verses DOT 3-4 brake fluids. The important technical issues governing the use of a particular specification brake fluid are as follows:

1. Fluid compatibility with the brake system rubber, plastic and metal components.
2. Water absorption and corrosion.
3. Fluid boiling point and other physical characteristics.
4. Brake system contamination and sludging.

Brake system materials must be compatible with the system fluid. Compatibility is determined by chemistry, and no amount of advertising, wishful thinking or rationalizing can change the science of chemical compatibility. Both DOT 3-4 and DOT 5 fluids are compatible with most brake system materials except in the case some silicone rubber external components such as caliper piston boots, which are attacked by silicon fluids and greases.

DOT 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition [possible brake failure -ed.].

from the Airheads BMW Club newsletter - July 1995

my questions is, is dot 5 bad? my friend brought this to my attention and am wondering the same question myself. . . if anyone could clear this up for me it would be great.

thanks

reikoshea · 08-15-2006, 08:44 PM

sounds right to me. i do know that dot5 shouldnt be used in regular brake system. the explination above seems very familiar.

Calesta · 08-15-2006, 10:42 PM

Yup, no DOT5 unless your brakes are designed for it. The metal parts of your system shouldn't care what DOT fluid you have, but the rubber parts do- and DOT5 sucks up water like nobody's business.

phyregod · 08-15-2006, 11:58 PM

Dot 5 is synthetic.. which is trash. Get dot 4 in non synthetic ftw!

MikeBergy · 08-16-2006, 03:41 AM

no complaints about my synthetic DOT 3/4 fluid...

pissedoffsol · 08-16-2006, 01:24 PM

smurf giz FTW!

MikeBergy · 08-16-2006, 06:56 PM

Quote:

Originally Posted by pissedoffsol

smurf giz FTW!

that stuff is expensive. I have yet to see one instance of where I actually needed that kind of fluid performance. I guess I'll find out in december.

E_SolSi · 08-16-2006, 08:15 PM

smurff jizz isnt that expensive
$10-16 per quart and it only takes about half a quart to do your whole brake system
so based on a yearly flush through it will cost you $5-8 per year to use smurf jizz
i hardly think thats expensive
i waste more than that every day on shit i cant even remember

even if you only run it as insurance in the rare instance that you MIGHT need the added temp resistance $5-8 is pretty damn cheap if you ask me

S2k Awe · 08-16-2006, 08:24 PM

I like ATE Super Blue & Type 200. Same fluid, different colors, helps you know when you've flushed completly

E_SolSi · 08-16-2006, 11:56 PM

yep the blue is the "smurf jizz" we are talking about
excelent stuff
i have no complaints about it and it has stood up to all of the abuse ive put it through

GSRCRXsi · 08-17-2006, 01:33 AM

where do you buy it?

MikeBergy · 08-17-2006, 04:54 AM

Quote:

Originally Posted by E_SolSi

smurff jizz isnt that expensive
$10-16 per quart and it only takes about half a quart to do your whole brake system
so based on a yearly flush through it will cost you $5-8 per year to use smurf jizz
i hardly think thats expensive
i waste more than that every day on shit i cant even remember

even if you only run it as insurance in the rare instance that you MIGHT need the added temp resistance $5-8 is pretty damn cheap if you ask me

I remember seeing it cost more than that...hmm... must've been someone trying to rip people off then. I coulda sworn it was like 15$ for the little bottle, what is it, a pint?

Ian: Google is your friend...
Discount Super Blue Brake Fluid / ATE TYP 200 / SuperBlue - RaceShopper.com
ATE Super Blue Racing Brake Fluid
Turner Motorsport: Product ATESB
Amazon.com: ATE Super Blue Racing Brake Fluid Dot 4: Automotive
LOL, you can even buy it on Amazon!!!

CrazyAzn · 08-18-2006, 11:13 PM

im using some valvoline syn that exceedes dot3/4 standards. it has a boiling point of like 500F, which is pretty good in my opinion. . . but it was a bitch and some to bleed out the dot5 shit i put in

. . . live and learn i guess

jazzop · 09-15-2006, 12:30 AM

Quote:

Originally Posted by CrazyAzn

The important technical issues governing the use of a particular specification brake fluid are as follows:

1. Fluid compatibility with the brake system rubber, plastic and metal components.
2. Water absorption and corrosion.
3. Fluid boiling point and other physical characteristics.
4. Brake system contamination and sludging.

OK, folks, let's look at each of the above 4 items.

1. The critical item here is RUBBER. All brake fluids available today are compatible with every metal and plastic used in automotive brake systems since WWII. But natural rubber is a bitch. Anything other than silicone (aka DOT 5) brake fluid will eat away at natural rubber brake components (seals, boots, etc.). Guess what, Honda folks.... your brake systems do not contain natural rubber! In fact, natural rubber has not been part of the brake system of any car built after, say 1970 or so (I'm sure there are the rare exceptions, but let's agree that your Honda does NOT have natural rubber brake components, ok?). The bottom line is that if you are running a car under 30 years old, you may feel free to use ANY brake fluid you choose, from an equipment compatibility standpoint.

2. DOT 5 Silicone fluid is the only brake fluid that does NOT absorb water. This is good and bad. If your brake system has been properly filled with 100% (not 99.5%) DOT 5 and properly bled (remember, air contains water), then you should be fine. But since most people like to cut corners, any mixture of glycol-based (DOT 3 or 4 or 5.1) brake fluids will quickly absorb that water and create bubbles that will, when the car sits, rust out your brake lines from the inside; and, when the car drives hard, possible cause a "vapor-lock" style brake failure.

On the other hand, you could fill up your system with a glycol-based fluid, forget the silicone, and be just fine with whatever small amount of moisture happened to be in the lines, since it would dissolve throughout the whole system of fluid and only pose a problem if the proportion of water rose too high.

3. Boiling point is only an issue for high-performance applications. Yes, DOT 5 has a higher b.p. than DOT 3 or 4, but its quirky properties make it not suitable for most people. No offense intended, but I don't think the average rice boy has the attention to detail required to run a car with silicone fluid. Use DOT 4 Castrol GT/LMA. It's by far the best performance to forgiveness trade-off.

4. Contamination and sludging is going to be dependent on how well one flushes and maintains the system, not the fluid one uses. But as I said before, silicone fluid-- if allowed to mix with water-- will put all that water in one place in your system and potentially cause corrosion from the inside.

The quote in the OP had some crazy statement about how silicone rubber parts "are attacked by silicon [sic] fluids." This is ridiculous. Silicone (which is not the same a "silicon") brake fluid is like Johnson's Baby Shampoo. It doesn't corrode anything, much less something else made of silicone. It's the only brake fluid that won't eat your paint if you happen to spill some.

Hope this helps

CrazyAzn · 09-15-2006, 01:12 PM

that was interesting, thanks again dude makes me feel a slightly better. even though i already drained all the fluid from my car. But like i siad thanks for the info dude, its much appreicated.

TurboMirage · 09-15-2006, 01:42 PM

good writeup!

phyregod · 09-15-2006, 02:45 PM

Writeup or rant?

jazzop · 09-15-2006, 03:14 PM

Yes, maybe it's a bit of a rant. I own two classic British cars, and silicone brake fluid is a common issue in the old Brit car world. But it shouldn't even cross the minds of people who work with modern cars.

What's next? Someone starting a thread about converting their ignition system to magnetos because they don't require a battery or alternator?

CrazyAzn · 09-15-2006, 09:29 PM

HAHA, thats halarious. . . .

08-15-2006, 08:33 PM	#1
CrazyAzn Senior Member Join Date: Mar 2003 Posts: 345 iTrader: 0 / 0% Rep Power: 15	Dot 5 brake fluid = bad? well a friend of mine sent me this: a former materials engineering supervisor at a major automotive brake system supplier, I feel both qualified and obligated to inject some material science facts into the murky debate about DOT 5 verses DOT 3-4 brake fluids. The important technical issues governing the use of a particular specification brake fluid are as follows: 1. Fluid compatibility with the brake system rubber, plastic and metal components. 2. Water absorption and corrosion. 3. Fluid boiling point and other physical characteristics. 4. Brake system contamination and sludging. Brake system materials must be compatible with the system fluid. Compatibility is determined by chemistry, and no amount of advertising, wishful thinking or rationalizing can change the science of chemical compatibility. Both DOT 3-4 and DOT 5 fluids are compatible with most brake system materials except in the case some silicone rubber external components such as caliper piston boots, which are attacked by silicon fluids and greases. DOT 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition [possible brake failure -ed.]. from the Airheads BMW Club newsletter - July 1995 my questions is, is dot 5 bad? my friend brought this to my attention and am wondering the same question myself. . . if anyone could clear this up for me it would be great. thanks __________________ 89 EF build: Poorman's ITR 95 GSR bottom end, .25over b16 pistons Pr3 Zealautowerks compression = 11-8-1 ARP head studs, Stock head gasket S2 Pro series IM, w/ Hondata intake gasket Holley 68mm throttle body ITR 4-1 header, w/ 2.5 in magna flow exhaust ( sounds niceeeee btw) kteller 2.5 mandrel bend kit. PnP b16 head w/ dual valve springs and ITR cams Milled about .030 AEM hybrid CAI Running obd1 w/ p28 tuned on chrome Made 178 at churches w/ 2in exhaust and dc 4-2-1 header w/ 2 in collector.

08-15-2006, 10:42 PM	#3
Calesta Admin with a big stick Join Date: Sep 2002 Location: Lufkin, TX Age: 31 Posts: 23,895 iTrader: 0 / 0% Ride: 2003 S2000 Rep Power: 265	Yup, no DOT5 unless your brakes are designed for it. The metal parts of your system shouldn't care what DOT fluid you have, but the rubber parts do- and DOT5 sucks up water like nobody's business. __________________ DO NOT PM me with tech questions! Use the forums! Intercrew Auto Salon - (972) 485-8688

08-18-2006, 11:13 PM	#13
CrazyAzn Senior Member Join Date: Mar 2003 Posts: 345 iTrader: 0 / 0% Rep Power: 15	im using some valvoline syn that exceedes dot3/4 standards. it has a boiling point of like 500F, which is pretty good in my opinion. . . but it was a bitch and some to bleed out the dot5 shit i put in . . . live and learn i guess __________________ 89 EF build: Poorman's ITR 95 GSR bottom end, .25over b16 pistons Pr3 Zealautowerks compression = 11-8-1 ARP head studs, Stock head gasket S2 Pro series IM, w/ Hondata intake gasket Holley 68mm throttle body ITR 4-1 header, w/ 2.5 in magna flow exhaust ( sounds niceeeee btw) kteller 2.5 mandrel bend kit. PnP b16 head w/ dual valve springs and ITR cams Milled about .030 AEM hybrid CAI Running obd1 w/ p28 tuned on chrome Made 178 at churches w/ 2in exhaust and dc 4-2-1 header w/ 2 in collector.

09-15-2006, 01:42 PM	#16
TurboMirage Running on two cylinders Join Date: May 2003 Location: Southbridge, MA Age: 24 Posts: 16,181 iTrader: 0 / 0% Ride: 2000 Mitsubishi Lancer RPW E5 Coupe Rep Power: 219	good writeup! __________________ Home of the RPW built 2000 Lancer CC Coupe. See what is done to the Little EVO5


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08-16-2006, 01:24 PM	#6
pissedoffsol RETIRED Join Date: Sep 2002 Location: Retirement Home Age: 28 Posts: 49,974 iTrader: 2 / 100% Ride: Electric Scooter Blog Entries: 1 Rep Power: 529	smurf giz FTW!

08-16-2006, 08:24 PM	#9
S2k Awe Junior Member Join Date: Jul 2006 Location: Rock Hill, SC Posts: 93 iTrader: 0 / 0% Rep Power: 5	I like ATE Super Blue & Type 200. Same fluid, different colors, helps you know when you've flushed completly

09-15-2006, 01:12 PM	#15
CrazyAzn Senior Member Join Date: Mar 2003 Posts: 345 iTrader: 0 / 0% Rep Power: 15	that was interesting, thanks again dude makes me feel a slightly better. even though i already drained all the fluid from my car. But like i siad thanks for the info dude, its much appreicated.

09-15-2006, 03:14 PM	#18
jazzop Junior Member Join Date: Jul 2004 Posts: 11 iTrader: 0 / 0% Rep Power: 0	Yes, maybe it's a bit of a rant. I own two classic British cars, and silicone brake fluid is a common issue in the old Brit car world. But it shouldn't even cross the minds of people who work with modern cars. What's next? Someone starting a thread about converting their ignition system to magnetos because they don't require a battery or alternator?

09-15-2006, 09:29 PM	#19
CrazyAzn Senior Member Join Date: Mar 2003 Posts: 345 iTrader: 0 / 0% Rep Power: 15	HAHA, thats halarious. . . .

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Dot 5 brake fluid = bad?