I have bought 3 bottles of Wilwood Hi-Temp 570 racing brake fluid.
As soon as i received it i found out that it is DOT3.. I thought it should have been at least DOT4 prior ordering it.
Fact is that this fluid exceeds the required boiling points of both DOT4 and DOT5.1
I assume i will not have any problems with brake fluid boiling as the specs are really good.
I know that there is not any problems in mixing DOT3 with DOT4 or DOT5.1 in case i want to replace it al a later time, but maybe the chemistry of that DOT3 fluid is not compatible with the seals of my braking system?
I use Wilwood Powerlite front and Sierra calipers rear.

Do you need racing fluid then?

Dont mix brake fluids, you'll be downgrading the racing fluid if it'so much better than the others.

The question is whether a good DOT5.1 brake fluid would be for any reason recommended instead of a high-temp racing DOT3 fluid. Actually the Wilwood fluid has a really high dry boiling point of 300 degC while the AP Racing 5.1 fluid has only 275 deg C.
Why should i choose a 5.1 fluid with a lower boiling point than a racing DOT3 one?

My point was do you actually need a racing fluid?


The higher the temperature i assume the better it is.

Are you definately comparing both dry boiling points?

The general rule of thumb is high boiling point fluids are much more hydgroscopic, ie they have a shorter life.

Really no advantage better to use a normal cheaper DOT 4 or DOT 5.1 and change it often.

In the real world provided normal DOT 5.1 brake fluid is reasonably fresh you will run into the brake pad friction fading long before you get long pedal from fluid boiling.

[Edited on 29/1/12 by britishtrident]