[Shop-talk] Silicone brake fluid

[Bob Spidell]

Agree.  Usually, the recommended solvent is denatured alcohol (ethanol 
spiked with chemicals to make it undrinkable--well, you /could /drink 
it, but you wouldn't be a happy camper).  I used it to flush my 
Austin-Healey 3000's system decades ago and silicone has been in ever 
since with no issues (that I could attribute to the DoT 5).


On 5/16/2020 8:16 AM, Karl Vacek via Shop-talk wrote:
> Yes, unfortunately you do.
>
> Every silicone conversion failure I've ever heard of (I even cheated 
> on this process once and had a failure of my own) has involved 
> contamination with conventional fluid.  Flush all hard lines with 
> lacquer thinner or similar, all new rubber and hoses, only lubricate 
> the rubber with silicone fluid.
>
> I'd be sure to soak the rubber you've already installed in some sort 
> of solvent and even then say a prayer that the DOT 3 didn't get too 
> far into the rubber.  Conventional fluid is alcohol based, so alcohol 
> might be there way to soak the contaminated rubber, then dry well - 
> like a day or more, maybe in warm conditions.
>
> Seems that DOT 3 or 4 gets way into the rubber and eventually reacts 
> once it's in silicone fluid.  And then people blame the silicone fluid 
> for eating their rubber parts and hoses.
>
> Karl
>
> On May 16, 2020 9:14:23 AM Robert Nogueirao via Shop-talk 
> <shop-talk at autox.team.net> wrote:
>
>> I’m helping a friend rebuild her brake system. All new lines and 
>> hoses. I’ve rebuilt the calipers, brake cylinders and master cylinder 
>> and they are ready to install.
>> Here’s the problem:
>> In rebuilding the cylinders I coated the bores lightly with red brake 
>> grease and DOT 3
>> Fluid.  Now she tells me she may want to go with Silicone fluid.  
>> Does that mean I need to disassemble and wash out all the cylinders 
>> and calipers?
>> Thanks for any answers.
>>
>> Bob Nogueira
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/shop-talk/attachments/20200516/eec6c14d/attachment.htm>