Most people just know that brake fluid has to be checked and that it should never get low. They don't know that it should be flushed annually nor are most people aware of the variances and other differences in brake fluid and type.
DOT 2 Dry Boiling point 374 DOT 2 Wet Boiing pont
DOT 3 Dry Boiling point 401 DOT 3 Wet Boiling Point 284
DOT 4 Dry Boiling Point 446 DOT 4 Wet Boiling Point 311
DOT 5 Dry Boiling Point 500
DOT 5 Wet Boiling Point 356
* Fluid * DRY * WET
* Castrol LMA DOT 3/4 * 446 * 311
* Ford Heavy Duty DOT 3 * 550 * 290
* ATE Super Blue Racing * 536 * 392
* ATE TYP 200 * 536 * 392
* Motul Racing 600 * 585 * 421
* Castrol SRF * 590 * 518
* Performance Friction * 550 * 284
Castrol LMA is very good at rejecting moisture and may be kept in your brake system for a couple years. The LMA stands for Low Moisture Activity. This is the minimum quality stuff that I would use in my Grandma's Impala SS. It comes in plastic containers which do not have a long shelf life. Don't buy lots of this stuff at a time because moisture can make its way through the plastic containers.
Ford Heavy Duty DOT 3 is VERY inexpensive and is popular among racers because of its excellent dry boiling point. It absorbs moisture quickly, but the racers don't care since they change their fluid frequently. Comes in metal cans so it may be stored. I would not use this say, in my Grandma's Impala SS. The car sits more than it is driven, moisture would be rampant in the system. Keep this for the racers only.
ATE Super Blue Racing and ATE TYP 200 are the same brake fluid in two different colors (blue and amber, respectively). BMW recommends this brake fluid for their street cars because it, like Castrol LMA, absorbs moisture very slowly. The advantage over LMA is that ATE has a much better wet boiling point. You can put this stuff in your car and forget about it for a long time. An excellent choice for a weekend track car which also sees regular street duty. Comes in metal cans. This is what I use in my street cars, Prelude and G35.
Motul Racing 600 is a very exotic and expensive synthetic fluid
with high wet and dry boiling points. Too expensive for the street and
requires frequent changing due to its hygroscopic nature. Sold in plastic bottles. It is not suitable for the street because it absorbs moisture quickly.
Now a little more on wet and dry boiling point's what they are and how they impact your ability to stop safely (unless you're one of those who never changes your brake fluid or cares...and in that case, close your browser window now)
As water content in brake fluid increases over time, the boiling point decreases. Fluid with a reduced boiling point (or high water content) can create vapor by boiling in the caliper, or wheel cylinder. The result is sudden brake failure. And water in the brake fluid can contribute to corrosion of parts such as steel pistons and ABS modulators.
The end result is even though DOT 3 fluid is rated at greater than 401' F, in the typical 3 to 4 year old car with 3 to 4% moisture content, it could boil under 300' F. And if it has got more than 4% moisture, you may as well be running straight water! YIKES! Can you say CRAAASH?
Moral: Flush your brake fluid every year or so. But only if you would like it to work well scarcely an inch away from those toasty 500' F rotors during a couple of hard stops! Or would you rather have the squishy pedal of death?