Installing a hydraulic pump on an excavator requires careful preparation and attention to safety. Here's a general guide on how to do it:

1. Safety First: Before starting any work, ensure the excavator is turned off, and all safety measures are in place. Chock the tracks, engage the parking brake, and use support stands if needed.

2. Gather Tools and Equipment: Prepare all the necessary tools and equipment required for the installation. This may include wrenches, sockets, screwdrivers, hydraulic hose, fittings, and a hydraulic pump.

3. Locate the Old Pump: Find the existing hydraulic pump on the excavator. Depending on the make and model, it can be located in different areas, such as the engine compartment or under the cab.

4. Drain Hydraulic Fluid: Carefully drain the hydraulic fluid from the system. Use a drain pan to collect the fluid for proper disposal.

5. Disconnect the Old Pump: Loosen and disconnect all hydraulic hoses and fittings connected to the old pump. Take note of the hose routing and connections for the new pump installation.

6. Remove the Old Pump: Unbolt and remove the old pump from its mounting location. It might require some force, so be cautious while handling heavy components.

7. Mount the New Pump: Position the new hydraulic pump in place and secure it with the appropriate bolts. Make sure the pump is properly aligned with other components.

8. Connect Hydraulic Hoses: Reattach the hydraulic hoses to the new pump using the correct fittings. Tighten the connections securely to prevent leaks.

9. Fill Hydraulic Fluid: Fill the hydraulic system with the recommended hydraulic fluid. Check the excavator's manual for the appropriate fluid type and level.

10. Bleed Air from the System: Start the excavator and slowly operate the hydraulic functions to bleed air from the system. Check for any leaks and tighten connections if necessary.

11. Test the Pump: Once the system is bled and operational, test the new hydraulic pump to ensure it functions correctly and delivers the required hydraulic pressure.

12. Conduct Final Checks: Verify all connections and fittings are tight, and there are no leaks in the hydraulic system. Ensure all safety measures are followed before operating the excavator.

Please note that the installation process can vary depending on the specific excavator model and the type of hydraulic pump being installed. Always consult the excavator's manual and, if unsure, seek assistance from a qualified mechanic or service technician. Improper installation can lead to equipment damage and personal injury.