Roger Elliott wrote:
> In the early 1900's Castrol was a lubricant made by Wakefield Oil
> from Castor Oil the name Castrol was a contraction of that. I assume
> the company changed the name to Castrol because the product was
> successful. It is no longer made from Castor Oil. When I was using
> normal brake fluid. I tried to use Castrol LMA (low moisture
> activity) when I could find it - which was not all of the time. I have
> now switched to silicone brake fluid in my Spitfire and will use it in
> my GT6 when I get it done.
>
> As others have said, other brake fluid will work.
>
Alright, maybe it's time to correct some misapprehensions, and provide
some real history. The original request from the poster in question was
whether or not Castrol LMA (which stands for Low Moisture Avidity, not
activity) was necessary to use to prevent the destruction of the rubber
parts in a replacement cylinder he bought.
That depends entirely on the time period in which the replacement
cylinder was made, and if it was NOS or a rebuilt unit. In the old, old
days, the rubbers in the cylinders were made with a variant of natural
rubber, and mineral-based brake fluids _would_ attack those rubbers.
The Castrol brake fluid of the time was safe for use with those rubber
parts, as it _was_ vegetable-based (specifically, from oils extracted
from castor beans). Castrol LMA is _not_ of that formulation. Rather,
it bears the Castrol name, but is not the original formulation used when
natural rubber was used in the rubber parts.
Since the end of the `60s, virtually all rubber replacement parts for
brakes are formulated with variants of nitrile rubber, which is not
attacked by mineral-based brake fluids. I'm not positive about the
cut-off dates, but it likely comes around 1968, when a number of notable
changes in NHTSA-mandated rules occurred. I do know that the
five-year-old `63 Spitfire I bought in 1968 did not tolerate
mineral-based brake fluid, and the ruptured rubbers sent me skittering
down the yellow line between opposing lanes of traffic during afternoon
rush hour in downtown Honolulu.
If the cylinder in question is not NOS, or was rebuilt at a date later
than the late `60s, the use of _any_ mineral-based fluid is likely okay.
The original question began with an error based on information provided
by the vendor, which suggested that Castrol LMA was the same as its much
earlier formulation--which is untrue.
So, quite simply, if the cylinder in question is NOS from the early- to
mid-`60s, it should be rebuilt with a current rebuild kit, so that it
has rubbers equal to brake fluid used. If it is not, then almost any
currently-available fluid is permissible for normal use.
Cheers.
--
Michael D. Porter
Roswell, NM
Never let anyone drive you crazy when you know it's within walking distance....
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