Originally Posted by bigjae1976
Why? Never heard that. I know DOT5 is incompatible. But you can mix DOT 3 and 4. I believe Castrol is DOT4. So how does it work when you initially bleed the SRF into the brake system that has non-SRF fluid? Some of the old fluid will mix.
That's what I've read and it's also stated in that thread.