MIL-PRF-46176B, PERFORMANCE SPECIFICATION BRAKE FLUID, SILICONE, AUTOMOTIVE, ALL-WEATHER, OPERATIONAL AND PRESERVATIVE (10 JAN 2001) [SUPERSEDING MIL-B-46176A]., This specification covers silicone-based hydraulic brake fluid for use in hydraulic brake systems at ambient temperatures ranging from +55°C to -55°C. The fluid is identified by military symbol BFS and NATO code No. H-547 (see 6.1).