Brake fluid

slantsixdan said

I suggest not using silicone-based (DOT 5) fluid. Its non-hygroscopic nature (i.e., its not absorbing water) is not definitely a good thing. Moisture gets into the brake hydraulic system -- it will happen with normal usage and/or changes in ambient temperature and humidity. Ordinary brake fluid is designed to absorb and assimilate a fair amount of moisture without causing substantial corrosion problems. With silicone fluid, the water will accumulate in slugs at the lowest points of the system...and stay there, where it will aggressively corrode whatever it's touching. This is not an improvement.

Furthermore, it is difficult to get all the air out of silicone brake fluid, so it is difficult to get a good, firm pedal.

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Having 4 "A" bodys with silicone DOT 5 brake fluid I have yet to see any of the problems outlined above. The non-hygroscopic nature (i.e., its not absorbing water) does just the opposite of what you conclude above. I had to check when I had Stainless Steel rebuild the KH calipers on the 68 Barracuda and they were done in 1992, still no problems. As for the difficulty getting all the air out of silicone brake fluid, "so it is difficult to get a good, firm pedal", all 4 cars are manual disc brakes, 2 KH and 2 73 up BBP systems, all have rock solid pedals. As always, one should do your homework, and make your own decisions. There is a lot of misinformation out there as well as pluses and minuses. Use what works best for your intended usage.