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Discussion Starter #1
Ok I'm about to install all new brake hardware and some new brake lines as well. Most all the old DOT3 brake fluid has been drained so I need to refill the system and rebleed the master cylinder and brake system.

Can anybody recommend a good fluid to use? Something good for a daily driver/weekend warrior that will promote high speed braking and minimize brake fade perhaps?
 

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In my opinion all dot 3 are about the same and all dot 4 are about the same. The dot number is a requirement the manufacturer needs to meet to put it on there. Like 22dodge said dot 4 has a higher boiling point. The most inportant thing to remember is brake fluid absorbs moisture. So don't leave the can lid or master cylinder lid off very long. I buy my brake fluid in gallons and when I open one I imediatley transfer it into 3 old quart brake fluid bottles and 2 pint cans and I keep them sealed until use.
There is aslo a silicon brake fluid out there. Very expensive and depending on where you read it it can and can't be mixed with a dot 3 or 4. I did my own tests and feel IT SHOULD NOT BE MIXED. I put silicon fluid in my charger when I put it together for a few reasons 1. I replaced everything in the system. 2. It does not eat paint like Dot 3 or 4 will. I believe it also has even a higher boiling point. I did not need that point 1 and 2 were the main reasons. Also silicon fluid does not absorb moisture it does just the opposite. Any moisture in it will sit in the bottom of your calipers and wheel cylinders in little puddles rusting things away.
Just keep in mind any fluid you use everytime you take the cap off it will draw in moisture. It does not hurt to change it once a year or so.
A parts man I use to deal with when I was up north did this 20 years ago. I thought it was too much BUT he put 200,000 miles on that new truck with out replacing any hydraulic parts.
Tim
 

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Discussion Starter #5
Do I have to get all the DOT 3 fluid out before putting DOT 4 in, or does that only apply when switching to synthetic?

Can I just drain the old DOT 3 fluid out and blow everything out with compressed air, or do I REALLY need to flush the old stuff out somehow?
 

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Discussion Starter #8
Thanks; I just learned a lot more than I thought I would about brake fluid. I'm going to try and get the ATE Super Blue. Any idea where I can get this stuff? Is it DOT 3 or DOT 4? The link provided wasn't very clear on this.
 

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Discussion Starter #10
OK, I've decided to get either the Ford Heavy Duty DOT3 fluid, or NAPA DOT4. The NAPA fluid is also 'low moisture absorbtion' which would be nice for a daily driver.

Wet/Dry boiling points:
Ford DOT3: 550/290
NAPA DOT4: 446/311

What does the wet/dry boiling point mean anyway???
 

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do not use DOT 5 (silicone) brake fluid on anything unless its a Model T and you drive it infrequently. Yes, you have to completely purge the system of glycol based stuff in order to use silicone.

Dot 3 and 4 are compatable (you can mix them), but not comparable in performance. As for that synthetic based Dot 4 they sell, I think it is the best stuff you can get for ANY car. It will last longer than regular brake fluid and preform better under high heat, just like synth engine oil! Go with that Napa Dot 4 stuff. Dot 4 came out as a premium alternative. the reason most manufactureres specify Dot 3, is because its standard duty for everything built in the last few decades!
 

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Brake fluid is hydroscopic, meaning it absorbs moisture. the wet boiling point is when it is "fully absorbed", which is what most daily drivers should go by since the fluid is kept in the system longer than say a race car. The dry boiling point is when it is fresh out of the can. I bleed my brakes before every track event so in that case the dry boiling boint is relevent.
 

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Discussion Starter #13
csracer - what brake fluid do you recommend for a street/weekend warrior car?

If DOT5 is silicone and not hydroscopic, does this mean it only has a dry boiling point?

Every part of my brake system is new (SLH III on GLH) so I'd like to use the best stuff for my application. I also need something I can buy locally. I wanted to use the ATE Super Blue, but I can't find in anywhere except on the internet.
 

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No, the problem with silicone brake fluid is when it does get moisture in the brake system the moisture goes exactly where you do not want it. It will settle to the lowest point in the brake system which is usually the calipers or wheel cylinders. When that happens you have a nice low boiling point of 212 deg F! I do not recomend the use of Dot 5 in anything you actually plan on driving. Dot 5 silicone fluid CAN NOT be used in a vehicle with ABS.
 

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Discussion Starter #15
Gotcha, no DOT5 for my cars.

It looks like the Ford stuff is the way to go. It's cheap, I can get it locally at any time, and it has a high dry boiling point. I bleed my brakes every 6 months and I live in a dry climate too so I shouldn't have to worry about moisture getting in the system.

Thanks for all the good info everyone; great thread.
 

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Dot 3 and 4 absord moisture from the air whereas Dot 5 actually absorbs the air. Dot 5 is in common use among high dollar race teams where the brake system gets completely flushed before each race.

Personally I use Motul RBF600. High dry and wet boiling temp. Before I used the Motul, I boiled the brake fluid out of my Omni at Buttonwillow race track.
 

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iTurbo said:
csracer - what brake fluid do you recommend for a street/weekend warrior car?
Sounds like you have already made your decision, but since you asked, i would recommend the ford HD , I have used it and many open track/road course guys swear by it because it works, it is cheap and it is available.
 
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