Duncan,
Yes, now that you mention it, that does ring a bell. I believe the early DOT
5 fluids would not swell the rubber at all and had leakage problems. I
remember someone (Tom?) suggesting soaking the seals in DOT 4 for a few
hours before assembly to "condition" them. I've heard that the newer DOT 5
fluids have an additive that swells and softens the rubber. I wouldn't
consider actual fluid leakage as a cause for "sponginess". I think you can
feel the difference and if it's bad enough to be noticeable to the foot,
you'll know it's a leak pretty darned quickly. If you had soft pedal when
the brakes were cold, then you had air in the system. If they got soft after
they were warmed up, then you had moisture.
Bob
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