When it’s time to install a new hydraulic pump, restarting the system is more complex than a routine daily start-up. Over time, maintenance teams may be less familiar with the process, especially if the previous pump operated without issues for an extended period. After pump failure, debris from the old pump often contaminates system lines, components, and the reservoir, requiring extra steps to restore system health. Here’s a practical guide for a smooth restart.
1. Clean & Refill the Reservoir
- Begin by removing the hydraulic oil from the reservoir using a filter cart.
- Thoroughly clean the reservoir and flush all hydraulic lines and hoses. Replace any visibly worn hoses while the system is drained.
- Refill the reservoir using a 5-micron filter cart, either with new oil or by recirculating the existing fluid through the filter for at least two hours.
- Use fresh, mineral-based oil with anti-wear, anti-foam, and anti-rust additives (e.g., AW-68 or AW-32). Circulate new fluids through the filter cart to clear any residual debris.
2. Replace Filter Elements
- Install “beta-rated” filter elements. A 10-micron filter is sufficient for systems under 1,000 PSI, but use 5-micron filters for higher pressures.
- For systems with servo or proportional valves, we recommend 3-micron filters for finer filtration.
3. Check the Main System Relief
- Inspect the main system relief for any debris around the main spool and control piston to ensure proper function. Refer to the manufacturer’s technical documentation for specific guidance.
4. Fill the Hydraulic Pump Housing
- Before starting, fill the pump housing with clean, filtered oil through the “top” case drain port if available. Allow any trapped air to escape, ensuring the housing is filled completely with oil.
5. Confirm Pump Rotation
- Verify correct pump rotation by viewing the shaft end. Typically, right-hand rotation appears clockwise and left-hand rotation counterclockwise when viewed from this angle.
6. Adjust Compensator & Relief Valve
- Initially, set the compensator and/or relief valve to a low pressure for startup. Once the pump is running, adjust to the desired system pressure.
- If both are present, set the relief valve at least 15% higher than the compensator to avoid unnecessary triggering. For fixed-volume pumps, only the system relief valve is adjustable.
7. Start the Pump
- Expect some initial noise as air clears from the lines and components. If noise persists, shut down and inspect the suction-side fittings for possible air leaks.
- After startup, check the reservoir level and top off as needed.
This procedure helps establish a healthy hydraulic system for efficient operation and longevity. Following these steps ensures your system is free from contamination and ready for peak performance.