> North American formulations of DOT 3 and DOT 4 will cause
> natural rubber
> seals to soften, swell and leak in a very short period of
> time.
Yes indeed !
I didn't believe that when I first started owning Triumphs, but proved it
beyond doubt on my TR3A back in 1978. Replaced every seal in the system,
flushed & filled with an American DOT 3 brake fluid (Wagner as I recall);
then parked the car for a month. When I came back, 3 different cylinders
had clearly leaked, and the reservoir was down to 1/2.
Repeated the experiment with Castrol brake fluid (might have been LMA, but
not sure about that); and the results lasted for several years.
Of course, come to think of it, that's the same car where one of the hard
lines rotted through from the inside. (Likely the next failure after
filling with Castrol.) The brakes had been fine just a few weeks before,
but when I jumped in and headed down the hill into the parking garage, the
pedal just flopped to the floor. The resulting accident was minor, but I
wound up losing the car anyway.
But brake seals get old just laying on the shelf; so I wouldn't use New Old
Stock brake seals anyway. And the natural rubber seals have apparently not
been made for many, many years.
Randall
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