Couple of reasons. The silicone fluid is compressable, and can lead to a spongy pedal. Silicone will not mix with moisture that enters the system. By not mixing with moisture, the water will pool in the low parts of the system, causing rust and crud to build up. It's much better to use a standard brake fluid and change it periodacally to flush out the moisture and dirt. Silicone fluid is fine for a car that's in a museum , but not for a car that sees frequent use.Originally posted by Big Easy:
I have the Wilwood pedal assembly.
Any idea why Wilwood recommends against Dot 5 Silicon brake fluid?