Fluid for Girling hydraulic components

["content22207" <brobertson@xxxx>]

AMC used Girling master/slave cylinders in their clutch systems
1980-1986. Factory literature (including big tech manuals) only
mentions AMC brand brake fluid (of course) or any other fluid meeting
DOT *3* specs. My high school car (still active in the stable) ran for
years on various house brands no sweat.

I think several things hurt Girling component users:
1) Only lubricant between rubber seal and metal cylinder is brake
fluid. If the component isn't used often, surface on far side of
piston travel dries out. Rubber drags across dry metal for at least
first petal push, resulting in accelerated wear (notice only outer
tapered edge of seal actually touches cylinder wall).
2) Girling components are made out of pot metal, not aluminum (at
least AMC's were). Will rust and pit. Only protection over piston
travel is layer of brake fluid. If not used often, rubber seal may
also end up dragging across rough surface.
3) Rebuilt components are honed, resulting in slightly oversized
cylinders. You'd think slightly larger seals would also be used but
appear not to be (at least not by Brakeware, or whatever brand has the
stoplight on it's label, sold by Autozone and Advance). After living
off factory slave cylinder for a decade or so, started burning through
rebuilt units every 2-3 years. Only a NOS cylinder purchased at
national convention 1998 has performed like the original (makes sense,
eh?).

As mentioned by David T, changing fluid regularly is probably more
important than any particular brand (folklore notwithstanding). To
that I'd add regular component use.

Bill Robertson
#5939