Chris Kotting had this to say:
>...
>If you assume that DOT 5 and SBBF are the same (which they aren't but
>this is the last time I will say that), I suppose if you hold your head
>just right, this is theoretically true. But in the real world, if SBBF
>doesn't absorb water (as the writer notes), and it's put into a clean
>system (as the writer recommends), how is the water that's supposed to
>be catastrophically "pooling" going to get in there in the first place?
>Inquiring minds want to know.
The question is, is there ANY brake fluid commercially available which is
rated DOT 5 and is NOT silicone-based? If not, then we might as well
consider them the same thing*. No need to get "huffy" about it <g>.
Admittedly, this "DOT 5.1" thing does confuse the issue.
As for the water, it can (and does) condense out of the air in the master
cylinder (which, you may have noticed, has a breather hole in the cap).
>...
>> DOT 5 is slightly compressible (giving a very slightly soft pedal),
>
>I can't believe that these two statements are right together. Brake
>fluid (regardless of composition) is a liquid. Liquids don't compress.
>Displace, yes, but not compress. That's how hydraulics work to multiply
>force. However, AIR will compress, and as noted, it is all too easy to
>still have air in a system with SBBF...
Hmmm, I don't think you are correct here. It's true that water doesn't
compress. And hydraulic fluids are chosen from among the liquids that do
not compress (hopefully!). But I don't think you can make a blanket
statement to the effect that ALL liquids don't compress. But it's been a
long time since chemistry class...
*I suspect the actual sequence of events was that, first, someone
formulated a silicone-based brake fluid; and then, secondly, the DOT
wrote up a spec based on the measured properties. If so, then there would
not be any good reason to make a distinction...
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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