>Does anyone out there remember hearing that only Castrol brake
>fluid should be used with British-made rubber parts such as clutch op-
>erating cylinders, due to some incompatability of their o-rings & seals
>and common US-made brake fluid?? That's in the back of my mind from
>somewhere, don't know if it's true now, or ever was.
That's what my local mechanic told me. It may be coincidence, but I rebuilt
my clutch master cylinder last year and initially used DOT 3. Ever since I've
noticed that the brake fuid in the clutch reservoir has been gray, with little
black bits resting in the bottom. I switched over to DOT 4 soon after I was
told about this, but I'm planning on rebuilding the master cylinder again Real
Soon Now.
For another data point, I also used the DOT 3 when I rebuilt the brake system,
and I've not noticed any problems there (knock wood).
As far as silicone fluid (DOT 5) goes, I'll stick with DOT 4. From what I can
gather, DOT 3/4 absorbs moisture and the water becomes dispersed throughout
the system. DOT 5 (silicone) is non-hygroscopic and, although that means it
won't absorb any moisture from the air, if any water does get into the system
it will just sit there in one big blob. Not Good if the blob happens to rest
right
next to the brake piston. I also understand that to switch to DOT 5 one needs
to completely flush and clean the existing brake system. So I think I'll just
remember to flush out the lines with new DOT 4 every year or so.
- BAK -
Bruce A. Krobusek
Rochester NY
tinyhost@aol.com
CIS: 74106,1335
'83 R80RT
'72 TR6 CC75665LO
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