Brake Oil is a hydraulic fluids used in hydraulic brakes and hydraulic clutch. It is used to transfer force into pressure, and to amplify braking force. It works because liquids are not appreciably compressible. Brake Oil is a lubricant used designed to protect vital components, including the gears and bearings in the drive axles and differentials, transmissions, industrial gear boxes and power take-off units. Gear oil generally has a higher viscosity for easier distribution and protection through the entire gear set.
When it comes to lubricants, especially for axles, the stance among fleet owners and operators has traditionally been that thicker viscosity is better. After all, thick lubricants do protect. Gear oil must protect critical hardware within the axle while operating in extremely demanding conditions.
For reliable, consistent brake system operation, brake fluid must maintain a constant viscosity under a wide range of temperatures, including extreme cold.