I use ATE Super Blu and ATE Typ 200 in my Lotus Sport Elise for which I need fluid that is as good as it can get for the track, while still being good for road use. The ATE fluid is DOT 4, but its wet and dry boiling points are well in excess of those of most DOT 5.1 fluids, and are higher than just about everything except the most exotic super expensive racing fluids.
However, that having been said, I can't see any reason for 99% of the people to upgrade to DOT 5.1 unless they have worked through their other braking problems.
If your current brake fluid is not boiling off and filling with bubbles, then your fluid is not responsible for your brake fade, and it will make no difference to your braking performance or feel.
What people need to realize is that brake fluid is designed to absorb water because the water is very insidious, and at a rate of molecule by molecule, it will make its way into the braking system, even when there are no leaks, by going in through atomic sized holes in seals where liquid water or fluid cannot pass. Overtime, this entering water vapor would cause corrosion. to prevent that, fluids are designed to absorb moisture so prevent it from cauding corrosion.
This is happening ALL the time. It accelerates sharply during monsoon and wet seasons.
As the fluid absorbs water, its viscosity changes, and its boiling pressure comes down. therefore the pedal feel changes, and if you perform hard braking, such as when a man runs across the highway as you are going at high speed and you brake hard, you can cause localized boiling of the moisture laden brake fluid. This causes the moisture to boil out of the fluid and form bubbles. THese make the brake pedal squishy because the bubbles compress when you apply pressure on the pedal and not enough pressure is transfered to the pads.
So if your existing fluid has become moisture laden, and perhaps boiled at some stage, changing the fluid will make the pedal feel much better. If you happen to replace it with a higher grade fluid, it will feel like that fluid is responsible for the improved feel, but it is not. it is the newness rather than the spec that improve the pedal feel.
This constant absorption of moisture by the fluid is the reason why you should replace your fluid atleast annually.
Of course it never hurts to go to a higher spec fluid, because that will ensure boiling doesn't happen so easily, wether the fluid is wet or dry. but do not look upon higher spec fluid to cure fade problems if your problem is not caused by fluid that boils too easily for the pace at which you drive.
get some fresh fluid, make it DOT 5.1 if you want (though ATE Super Blue and ATE Typ 200 DOT 4 are the best), and fit better pads and discs. fit stainless steel brake lines.
and oh yeah, another big deal. most brake fluid is sold in plastic containers. this is stupid because just as water molecules make their way into the braking system (which is why the fluid is designed to absorb water), water molecules also make their way THROUGH the plastic walls of the container. This sounds absolutely ubelievable, but believe me, it is true, and in this critical application, the extent to which it happens is enough to matter. If the fluid is used soon after packaging, there is no problem, but if its been shipped by sea, then sat on the port, then got shipped and sat in the warehouse then sat in the shop, well its been absorbing water all this time. reducing how much more water it can absorb once it goes in your car, in effect already being wet by the time it goes in the car, and already suffering from a reduced boiling point and greater prospensity to boil.
This is why the really quality fluids come in metal containers.
Also, when you get new pads and/or discs, you have to follow a bed in procedure. virtually nobody does and it doesn't matter for the average bloke, but if a spirited driver doesn't follow the bedding in process, he'll end up with pads that are prone to glazing and fading and cannot develop solid consistent friction on the discs, and will get inadequate braking.
So in short, there is a lot to getting the best braking from your car, and just upgrading the fluid isn't going to do much on its own.
Last edited by Harbir : 29th March 2009 at 04:38.
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