1. 8456-1. Which of the following safeguards ensures proper system operation and mitigates damage to non-metallic components of the hydraulic system? A. The manual bleed valve should be closed prior to servicing hydraulic fluid to prevent fluid loss as the cap is being removed. B. Before assembly of any hydraulic components, seals and gaskets should be inspected and replaced only if they show signs of wear or leakage. C. When adding fluid to a system, use the type specified in the aircraft manufacturer’s maintenance manual or on the instruction plate affixed to the reservoir or unit being serviced.