>
> OK, ROLAND,
>
> Drop the other shoe. What is your conclusion? Silicone or Lucas
> replacement for Girling? Since I just replaced my clutch system with new
> parts, including silicone, I am wondering if I made a mistake.
>
> I am surprised about leaking of moisture thru the seals. I presume you
> mean those betweeen the air and the fluid at the master and slave
> cylinders. Don't get much water inside the car (where the master
> cylinder seals are), unless it's raining. If moisture laden air (50%
> R.H. is normally considered "comfortable', and there isn't really a lot
> of water mass at 70-85 deg F. in the air), you're saying air gets passed
> those seals too. This would make for "spongy" pedals, and require
> consistent bleeeding, regardless of the fluid. I don't think that the
> amount of air necessary to contain "tablespoons" of water wouldn't be
> immediately noticible as spongy pedal.
>
> Bottom line. Silicone, Hydraulic fluid, or punt to another source?
> --
> Steve Laifman < One first kiss, >
>
I think the water supposedly gets past the slave/wheel cylinders which
are directly exposed to water. No doubt some moisture also get obsorbed
from the air. Because glycol (which is a type of alcolhol) is
hydroscopic, absorbed water evenly distributes itself throughout the
system. By the way this water is dissolved, not held in suspension as
someone stated.
I went back and forth on this when I was doing the brakes because I had
everything disassembled and could go either way. After talking to a
Brit car mechanic I knew who was also a fellow Cobra owner, I opted for
LMA. But it was a close call. If my car sat a lot, I probably would
have gone with silicone. Silcone does have a problem with sponginess
when the brake get hot, and it also compresses a bit more so this can
increase the problem a bit. Small-block Cobras with street calipers
already have a problem with spongy brakes because of their very long
flexible hoses. I figured I dnd't need to add to this. Now one of my
spring ritules is to flush the brakes and clutch. I have heard from
several sources that silicone fluid is very hard on brake light
swithces- the old presure type, but this could be due to bad luck.
One other thing. You can not get all of the old fluid out by merely
flushing. In the mid '60s, right after I bought my car I flushed out
all of the Girling Crimson fluid that was in the brakes and clutch with
alcohol and compressed air and refilled with some Ford disk brake fluid
recommeded by the Cobra crowd at the time. When I took the brakes apart
a few years ago, I found plenty red fluid in the calipers and fittings.
BTW the non Girling/Castrol fluid did NOT eat my Girling seals. IMO,
this is a myth. I know plenty of people who used plain old DOT 3 fluid
for year in their British Cars without a problem. What can damage your
brakes is neglect.
Roland
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