Doug & Rett Leithauser wrote:
> I've heard some negative comments about silicone fluid and water. Because
> the water does not mix with the fluid, any water that finds it's way into
> the system tends to collect at the lowest point and cause corrosion there.
> I assume that the water gets into the fluid over time as it does with
> regular fluid, but is not suspended in the fluid. I don't have a good
> answer, I suppose the moral of the story is to change the fluid regularly,
> regardless of what you use.
>
> Happy Motoring
> Doug Leithauser
Doug,
I believe you are "mostly" correct in your statement . The "regular" brake
fluid is hygroscopic (absorbs water) right out of the air. The Castrol brand
may be even more so, but it is the only regular brake fluid I know of that
doesn't eat the English rubber brake components, another killer. That's one
reason you can't leave an opened can around to "refill" your leak. It has
absorbed a lot of water in the closed can.
Regarding silicone based fluids. They are compatible with the English "saddle
rubber", the finest quality don't you know. They also do not absorb water.
If, however, you are changing over from a regular to a silicone system, and
have not replaced ALL the components, including line and coupling, there is a
possibility that residual moisture remains from the previous condition or
during repairs, and the synthetic will not absorb it. A wise precaution would
be to replace both the master and slave on the clutch, but not practical on
the brakes. The next step would be to flush the entire system with FRESH
Castrol Fluid until it runs clear and bubble free. Activate the pistons (step
on the pedal) a few times to allow fluid on all working surfaces. At this
point, you have absorbed all the residual moisture. Now you can start adding
the silicone on top of the hydraulic fluid. They do not mix, but add slowly.
Bleed the system, replenishing the synthetic, until all the system is
discharging only bubble free synthetic. Now there is no "residual moisture at
the lowest spot". This is costly in fluid, but worth it in the long run.
BTW: I just installed a pair of rubber cap inserts, from Tiger Technologies,
on both the brake and clutch master cylinders. These are like American units
and are built like an accordion. They are in direct contact with the fluid,
and if the fluid level lowers the seal follows it. In the current system air
enters the cap through a small hole and contacts the fluid. This allows new
moisture to enter the hydraulic fluid. Recommend no matter what fluid you
use. Also easy to read brake fluid level through the plastic, as the red
rubber boots are easily visible/.
Steve
--
Steve Laifman < One first kiss, >
B9472289 < one first love, and >
< one first win, is all >
< you get in this life. >
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