While paging through the latest Eckler's catalog that showed up today I noticed that they are selling silicone brake fluid (DOT 5) which they claim will not absorb water. Has anyone heard of this and is it true? Is there any reason I should not flush my existing fluid (needs to be done anyway) and use this instead? Its my understanding that the absorbtion of moisture is the single largest problem that brake fluid has and if that is so, wouldn't everyone want to be using it?

(they also say that it is NOT for use with ABS)

What I know about silicon brake fluid is that it has a higher boiling point so it will perform better in extreme conditions (like racing) and that it is less prone to aborbing moisture.

It was also recommended to me not to simply replace it in the brake system unless I was going with all new calipers. Guess it will leak around older piston seals easier than regular brake fluid.

Don't know anything about not using it with ABS.

|UPDATED|5/2/2003 12:14:03 AM|/UPDATED|

Silicone brake fluid is the stuff to use, but ONLY IF YOU COMPLETELY REMOVE the old fluid. That means completely! If not, you will get a gummey mess and NO BRAKES!

I only use it when I have replaced every component during a restoration, as it is very hard to ensure the old stuff is all removed.

Having said that, I have heard of people flushing their system with water to remove the old fluid, alcohol to remove the water then blowing the alcohol out with dry air or nitrogen.

If it were my car, I'd remove and disassemble everything and clean out the old fluid, or replace with rebuilt stuff before switching to silicone fluid. That includes the proportioning valve and lines, not just the master cyl and calipers.

Joe

I think I'll stick with the old fashioned DOT 3 stuff, I'm glad I asked!!

The stuff is great and I recommend it highly. But one draw back is that if there is any weakness in the connections, it will leak. It is much more prone to leaks than DOT 3. I have it in my 68 Vette and 74 Triumph TR6.

Mark

When I did the brakes in my 78 I switched to silicone fluid.
I used 2 quarts to flush out all the old stuff.It's been
8 years now with no leaks or other problems. Silicone fluid
won't absorb water but it does absorb air (don't shake the
bottle!) Anti lock brakes pump the fluid hard and the air
will come out of suspension and give you a mushy pedal.
The same thing may happen at high altitude-the air "boils
out". I've read that you should heat the fluid to 500F
to drive out the air or rebleed the brakes after a couple
of weeks,after it has had a chance to get hot but I have
done neither with great brakes. Take a chance and upgrade
your car to the 21st century!
Steve