👉 The spare fluid, also known as the reserve or back-up fluid, is an essential component in various mechanical systems, particularly in hydraulic and pneumatic systems. It serves as a backup to the primary fluid supply, ensuring that critical functions can continue even if the main fluid reservoir is depleted or contaminated. This fluid is typically stored in a separate tank and is used to maintain system operation until the primary supply can be restored or replenished. The spare fluid must meet specific quality standards to prevent damage to system components and ensure reliable performance.