Hey all, I have a few Q's about DOT 5 Brake Fluid.

1. Does it really have a higher boiling point?
2. Silicon-based, so it's "supposed" to be more paint friendly - is this true?
3. Did any of you running DOT 5 see any REAL benefits from it?
4. What brand(s) is/are the best? Thinking MOTUL, but need it sooner, so I might have to get some other DOT 5 **** from the local Honda Bike dealer.
5. Any downsides besides price? I saw $8.99 for 12fl.oz.
6. I am completely filling up a completely dry system. FULL bleed and all. How much fluid you guys think it will take?

That's about it. This is for my daily driven Civic hatch with swap and GS-R brakes at all 4 corners, stainless lines, Slotted Brembo rotors, Integra Booster, and Integra RS non-ABS master cylinder.

I don't care about the price as long as there are true benefits in the slightest way. Even the milder effects on paint (if true) would be enough for me to buy it. Sounds retarded I know, but I'm trying to keep the car as nice as possible for as long as possible.

Later!

 

the effects on paint aren't going to matter unless you plan on spilling on your body panels. But you are correct, DOT5 will not damage your paint, nor will it corrode your SS lines, or your other brake components.

it has a higher boiling point. DOT 5 has to have a boiling point above 500 degrees. DOT4 has to have a BP above 446 degrees (These are dry, your brake fluid will absorb water over time, lowering the BP, after 6 months or so, your BP would be around 425 with DOT 5).

With those big brakes on a civic hatch, your brakes should be overly worked.. But if you track the car, and see any sort of fade, some DOT5 or 6 may be a good idea. If you've never seen fade in your car before, you probably don't need the higher BP.

Of course, you don't have ABS so you're fine to use any of the fluids.

Motul is good stuff. Remember, not all DOT 5s are made the same, and some will have higher BPs and some lower. You may be able to find some good stuff at the honda bike dealer.

 

I don't think there is anyone in the Comp forum that uses DOT 5. They use mostly ATE Gold or something from Motul. I should add that most of them road race their cars often. Here is a recent topic. https://honda-tech.com/zerothread?id=156681


[Modified by G2LSS, 11:22 PM 4/15/2002]

 

#5 downside- it is not compatible with honda brake systems and if you use it, certain parts can fail as a result. look in a service manuel and they say NOT to use dot 5 fluid for the brakes. I'd stay away from that stuff.

 

Thanks for the help. I found that thread from Rodney too.

MOTUL RBF600 for me

 

For those who missed it in Comp.

Current Synthetic is DOT 5.1 glycol, and Silicone Synthetic is DOT 5 and are not synonymous, silicone came out in the '80's, i.e. that purple GE stuff. It's very squishy (compressible, like soft jello; yes in a fluid) due to its easy and lasting aeration (bubbles) ability.

It was designed for museum cars that don't get much use, to keep the internal brake components from corroding because it doesn't absorb moisture. Problem is that in a street car then moisture buildup from outdoor exposure/use isn't absorbed, instead collecting and causing rust, along with the squishy issue affecting the ABS.

DOT 3/4/5.1 glycol fluids all absorb moisture in suspension, and need to be changed somewhat regularly (yearly) to prevent pedal failure due to the lowered boiling point allowing possible gasification in the caliper. All are mix compatible, just flush out most of the old fluid. Do NOT use ATE Blue (200 Gold instead) if you autocross in Stock class. Motul is fine but expensive. Anything under $12/litre like ATE is good.