Brake fluid info...

[06vitzRS]

Some people are talking about using racing fluid (DOT5) in their brake systems. I would not and this is why:
There are 3 ratings, DOT3, DOT4, DOT5. 3&4 are glycol based and 5 is silicone based. Glycol based fluids are hygroscopic, which means they can absorb moisture. Silicone based is not. Any moisture in the system will collect in the lowest points of the system. The moisture winds up in the wheel cylinders and calipers. DOT 5 should not be used in ABS systems because the water can collect in the valves of the ABS system, corroding them and rendering them inoperative. Dot 5 is also more prone to trapping air in the fluid, especially when agitated, as happens in an ABS hydrolic controller or pump.
If you are going to use DOT5, at least change it often. DOT4 is good enough and way less to worry about.

[Klink10]

Very good point(s) made there. While in the process of putting my re-built powdercoated calipers on I plan on flushing the system with ATE brand Dot 4 fluid. Most reading I did in arriving at the decision to use ATE indicated that DOT 5 is used primarily in racing applications where the fluid is changed often.

[Loren]

Not all racing brake fluid is DOT5. Good high-temp DOT4 is available.

Regardless of what type you use, if you're using it on a track, the system should be bled (which will purge whatever is in the calipers) before each track day and flushed at least annually. In other words... DOT5 wouldn't be bad if the system is properly maintained.

That said, I use high-temp DOT4. Usually ATE, it's a good "bang for your buck" fluid considering temp vs. cost.

[cali yaris]

That said, I use high-temp DOT4. Usually ATE, it's a good "bang for your buck" fluid considering temp vs. cost.

+1 - that's what I use also.

[auxmike]

Does'nt putting DOT5 silicone into a DOT3 factory fill system mess up the seals though?:iono:

[YarisSedan]

I used valvoline synthetic high performance dot 4 fluid.