Question: Brake Fluid

[Vette79]

What's the best local "over-the-counter" brake fluid? Obviously, the higher the wet boiling point the better. I've just replaced my rear calipers and lines and this coming weekend I will be replacing my master cylinder. So, I'm looking for the best brake fluid to use as well as a bench bleeding kit. I have a NAPA, AutoZone, Pep Boys, and Advance Auto close by to purchase parts.

 

[Rex S]

We only use DOT 4 in the shop, CarQuest brand, as they must pass standards to carry the DOT 3, 4 or 5 rating. DOT 5 is a silicone based fluid that is great for older cars that sit a lot but many people complain it doesn't "feel" right as the pedal will always have a bit of sponginess that is normal. The high end fluids are for track day cars and the others that are actually used in performance driving and offer no advantage on the street.

 

[Vanity Plate Bob]

Can 3 and 4 be mixed in the system with good results?.
Lost a little in my 88 olds. A we bit is showing at the main cylinder but none underneath. Need to watch it closely now. I feel sure what he added was the cheapest available.
This took place yesterday.
Wife drives it and light in dash had been on, dimly, for a week or so.

 

[Vettehead Mikey]

DOT3 and DOT4 can be intermixed without problem, they are both glycol based. As for for which brand is best- it makes no difference. No street driven car gets their brakes anywhere near hot enough to approach the boiling point of the fluid. Changing the fluid every few years to rid the system of accumulated moisture (if any) is far more important than worrying about fancy labels on a can.

 

[Vette79]

DOT3 and DOT4 can be intermixed without problem, they are both glycol based. As for for which brand is best- it makes no difference. No street driven car gets their brakes anywhere near hot enough to approach the boiling point of the fluid. Changing the fluid every few years to rid the system of accumulated moisture (if any) is far more important than worrying about fancy labels on a can.

Yep, thats what I'm thinking. I initially went with ATE Super Blue and depleted that after several attempts bleeding the brakes. I think that stuff was overkill. Picked up some Valvoline Synthetic Dot 3 & 4 from AutoZone. Also, found a Master Cylinder Bench bleeding kit at NAPA for $8.

 

[White75]

Yep, thats what I'm thinking. I initially went with ATE Super Blue and depleted that after several attempts bleeding the brakes. I think that stuff was overkill. Picked up some Valvoline Synthetic Dot 3 & 4 from AutoZone. Also, found a Master Cylinder Bench bleeding kit at NAPA for $8.

SuperBlue is definitely overkill. It's great stuff if you track your car because of the high boiling point. I use it in my M3. However it LOVES water. Let me rephrase that, it LOVES water. I always flush it before a track day because the boiling point lowers significantly when it absorbs water.

In all my other cars I use a DOT 3 or 4. I've been happy with the stuff from walmart. It's cheap so if you are having problems bleeding brakes you won't be pouring money into the catch pan. I went through a few bottles when I did my brake replacement. If you're not cool with the walmart stuff you can put in the compatible name brand stuff and bleed again. However, even though it's cheap, the walmart brand still has to meet specs and is probably made by one of the name brand manufacturers.

 

[Evolution1980]

I've always heard good stuff about the "Ford Blue Dot 4" or something like that. Although I just have standard Dot 3 or 4 in my car. Nothing super special that I can recall.

 

[73shark]

One advantage with silicone besides its not liking water is that it won't hurt your paint if you get it all over it. Don't ask me how I know.

 

[Hib Halverson]

DOT3 and DOT4 can be intermixed without problem, they are both glycol based. As for for which brand is best- it makes no difference. No street driven car gets their brakes anywhere near hot enough to approach the boiling point of the fluid. Changing the fluid every few years to rid the system of accumulated moisture (if any) is far more important than worrying about fancy labels on a can.

Uh...Mikey...in re: your statement "no street driven car gets their brakes anywhere near hot enough to approach the boiling point of the fluid."....

Can you supply some facts to support that statement? Can you give us an insight to the test program you ran which provided the data on which you based that statement?

Next, your final statement implies that Corvetters should ignore information on brake fluid containers. Can you give us some background information about your level of expertise in engineering of automotive braking systems and, with respect to brake fluid, your expertise in chemical engineering? I ask about that because I think someone who advises people to ignore the DOT ratings printed on the labels of brake fluid containers needs to establish a very high level of credibility when giving such advice.

 

[Vettehead Mikey]

Bent out of shape over nothing- again. Man you gotta calm down. :eyerole Who said ignore anything?

Edit: Here ya go:

http://www.valvoline.com/car-care/automotive-system/brakes/ccr20081001v4

Note the bolded comments :

"The U.S. Department of Transportation has set boiling-point standards for brake fluids. The most common brake fluids are DOT 3 and DOT 4. Both are usually polyethylene glycol-based. Brand new DOT 3 boils at about 400 degrees. Top quality DOT 4 won’t boil until more than 500 degrees, though the legal minimum is about 450 degrees. That’s more than plenty unless you’re racing. "

Here's their view on moisture content which agrees with my comments above regarding frequent change:

"But add about three percent water—which is what the government does for testing—and the boiling point drops to less than 285 degrees for DOT 3, while DOT 4 falls at barely over 310 degrees. That’s cutting it close if you’re descending Independence Pass outside Aspen, Colo. with a loaded trailer."

Here's their views on upgrading; no apparent concerns about intermixing here:

"If your car came with DOT 3, it’s okay to upgrade to DOT 4, though DOT 3 is just fine for the vast majority of drivers. But if your car came with DOT 4, use only DOT 4 fluid. Both DOT 3 or DOT 4 work fine with most disc or drum brakes and anti-lock braking systems (ABS)."

Here's a product that bridges the gap:

http://www.valvoline.com/products/consumer-products/brake-fluids/dot-3-4-brake-fluid/28

 

[Vette79]

Bent out of shape over nothing- again. Man you gotta calm down. :eyerole Who said ignore anything?

Edit: Here ya go:

Valvoline.com > Car Care

Note the bolded comments :

"The U.S. Department of Transportation has set boiling-point standards for brake fluids. The most common brake fluids are DOT 3 and DOT 4. Both are usually polyethylene glycol-based. Brand new DOT 3 boils at about 400 degrees. Top quality DOT 4 won’t boil until more than 500 degrees, though the legal minimum is about 450 degrees. That’s more than plenty unless you’re racing. "

Here's their view on moisture content which agrees with my comments above regarding frequent change:

"But add about three percent water—which is what the government does for testing—and the boiling point drops to less than 285 degrees for DOT 3, while DOT 4 falls at barely over 310 degrees. That’s cutting it close if you’re descending Independence Pass outside Aspen, Colo. with a loaded trailer."

Here's their views on upgrading; no apparent concerns about intermixing here:

"If your car came with DOT 3, it’s okay to upgrade to DOT 4, though DOT 3 is just fine for the vast majority of drivers. But if your car came with DOT 4, use only DOT 4 fluid. Both DOT 3 or DOT 4 work fine with most disc or drum brakes and anti-lock braking systems (ABS)."

Here's a product that bridges the gap:

Valvoline.com > Products > Brake Fluids > DOT 3 4 Brake Fluid > Valvoline® DOT 3 & 4 Brake Fluid

This is what I ended up getting after doing some research. Just fine for street use.

Valvoline.com > Products > Brake Fluids > DOT 3 4 Brake Fluid > Valvoline® DOT 3 & 4 Brake Fluid