Having gone to the effort to use silicone fluid in my TD, I wouldn't
do it again.
While it's true that the stuff won't harm paint, a consideration with
leaky MGB master cylinders that drip onto the metal instead of onto the
ground, the "no water absorbtion" feature is not worth as much as it
would seem. Silicone does not absorb water, but water does continue
condense in the system. It works its way to the lowest point in the
hydraulics, brake cylinders, where it puddles. One must pump out a bit
of fluid every year to drain off the water that has accumulated, else the
wheel cylinders rust. One doesn't need to replace it, they say, but
getting the water out remains important maintenance.
Conventional fluid absorbs the water, so the maintenance is to push new
fluid throughout the system, but conventional fluid is cheap and the task
is pretty much the same for a teaspoon as for a pint.
Silicone seems to leak past rubber cups and seals that hold
conventional fluid OK, though why this should be I cannot explain. If a
bit leaks out, it can't be removed from brake shoes with brake cleaner,
whereas one can rinse a small bit of conventional fluid out in a pinch.
The one huge plus to silicone is that if you splash a bit into
your eyes it doesn't hurt a bit, unlike conventional fluid where you will
find the strength to lift the car yourself to get out from underneath.
It was introduced as a higher-temperature fluid, which it is, but
ordinary fluids now achieve temp resistance that is fine for the use we
give MGBs on the street.
Once it's in the car, someone has to remember, or tag the MC, so fluids
are not mixed when topping up.
I was an enthusiast for the silicone, but I don't see significant
advantages to it anymore.
TD with silicone
MGB-GT with DOT4
On Thu, 19 May 2005 16:54:39 +0100 "Gosling, Richard B"
> Well, on my BGT I'm bringing back to life, I plan to use DOT5
> silicone fluid
> - no possible paint damage, no water absorbtion, no need for regular
> replacement, by all accounts. I'll be buying from the MGB Hive, not
> what brand they sell.
> Richard & Nancy