Re: RE: silicone brake fluid

[Trisha Bethen <trishab@mv.mv.com>]

On Tue, 30 Jul 1996 Porsray@aol.com wrote:

> I have to go along with the recommendation of NOT using silicone fluid
> in cars that presently have DOT fluid.  You might feel it is inert, but it
> will not mix with the standard fluid.  Besides this, it is somewhat 
> compressible. I have read several articles in the Porsche Club magazine
> about not being able to get rid of a spongy pedal feel after switching
> to silicone.  Recommendation is that silicone should NOT be used
> for street cars; it is better recommended for show cars that get stored
> for long periods of time; then the silicone reduces the damage caused
> by hygroscopic action (absorption of water in the fluid).
> 
> Ray Calvo (porsray@aol.com)
>    
> 
> 
> 
> 
> In a message dated 96-07-29 12:47:30 EDT, you write:
> 
> << From: John Cooper <Jacques.Noir>
>  Date: Mon, 29 Jul 1996 09:33:18 -0600
>  Subject: Re: Silicone brake fluid
>  
>  At 03:59 07/27/96 +0000, you wrote:
>  >Mike wrote:
>  >
>  ><<
>  >I thought I had seen something a while back about using silicone brake
>  >fluid. However, searching the archives, I could find nothing. Is it ok
>  >to use Silicone brake fluid in a 91 200 Q or will it damage the ABS?
>  >>>
>  >
>  >>From what I understand, DO NOT USE DOT 5 (SILICONE) BRAKE FLUID IN AUDI
> ABS
>  >BRAKE SYSTEMS!!!!  (Sorry to shout but this is extremely important.)  Dot 5
>  >WILL damage critical seals within the system over time and you WILL be
>  >replacing the master/slave cylinder, not to mention some extremely
>  >high-dollar ABS component. ONLY use DOT 4 unless otherwise specified.
>  Check
>  >your owner's guide.
>  
>  Please be more specific.  Silicone brake fluid is used in many and is
>  compatible with many brakes systems.  What do you mean that some seals will
>  get damaged?  Silicone is NOT a mineral based fluid, as it sounds like you
>  might think.  Silicone Dot 5 fluid is about as inert as you can get.  If you
>  have more specific information as to what will happen, I would be very
>  interested to know, and what specific materials used in automotive braking
>  systems it affects. Thanks,
>  Coop


Hi all, Having been involved in racing for many years and for many, 
working specifically with improving brakes in cars with typically horrid 
Showroom Stock brakes and then having these cars move into improved 
touring where not much could be done with brakes other than pads and 
fluid and ducting.....Silicone (DOT 5) brake fluid was the huge 
no-no.....NO-NO....under normal and racing conditions, the heat will 
cause the organic or whatever substances to break down, causing brake 
failure in most instances.....I have seen the silicone take out 
seals....they end up cracking, becoming gummy, all sorts of failures....
My recommendation is a good DOT4 fluid designed for hi-temp use.....we 
used to use CARTEL but there are others on the market.....most are now 
compatible with DOT3 fluid because the showstock cars were limited to 
DOT3 and they all bitched.....DOW chemical did a tremendous amout of 
research on their fluids.....check with PEGASUS RACING or any good outfit 
supplying brake products to TRANS AM or WORLD CHALLENGE autos. 
Another good thing to do with your brake pads to avoid that awful "green 
fade" when you first use new pads....(hard pedal, no brake).....is to 
bake them......put the pads into an oven, set the oven to 450....turn it 
on for 30 min. then shut off and let the pads cool down 
naturally.....this removes the outgasses from the bonding material so it 
doesn't happen on the street or track.....we have used this process for 
over 12 years and swear by it....it's called 
RST's baked brakes. Enjoy