Graco Pump Rebuild By Greg from Graco - Best Tutorial Around

Introduction

Rebuilding a Graco pump can be challenging, but with the right guidance, it becomes a manageable task. This tutorial provides a step-by-step process for reassembling the ProConnect Endurance Pump, applicable to models from 190PC to 595PC. Follow these instructions to ensure a successful rebuild.

Step 1: Gather Necessary Tools and Parts

Before starting the rebuild, ensure you have the following:

• New replacement parts kit
• Torque wrench
• Vice (for holding piston assembly)
• C-spanner (for tightening fittings)
• Light oil (for soaking leather glands)

Key Components of the Pump

Familiarize yourself with the main parts:

• Main pump body (includes the cylinder)
• Pump inlet housing (holds the inlet ball, seat, and inlet cage)
• Pump piston (houses the piston valve)
• Piston rod
• Throat packing and nut

Step 2: Reassemble the Piston Assembly

1. Insert the Wiper: Place the wiper in the piston assembly, ensuring it opens in the right direction to clear the cylinder.
2. Add Packing Glands:
   • Insert the lower packing gland.
   • Add the packing stack (soaked in light oil).
   • Place the upper packing gland on top.
3. Install the Outlet Ball: Position the outlet ball and ensure it is seated correctly.
4. Assemble the Piston Valve: Combine all components and check that the ball is in place.

Important Torque Step

• Torque the Piston Valve: Use a torque wrench to tighten the piston valve to 37 Newton meters (±4). This step is crucial for maintaining pressure in the pump.

Step 3: Prepare the Pump Body

1. Attach Packing Glands:
   • Insert the lower packing gland.
   • Add the packing stack.
   • Place the upper packing gland.
2. Install the Throat Nut: Loosely attach the throat packing nut to avoid hindering the piston assembly.

Step 4: Assemble the Piston Rod and Valve

1. Insert the Piston Rod: Carefully place the piston rod assembly into the pump body.
2. Torque the Piston Rod: Use a 25 to 50 ml C-spanner to tighten according to the manual’s specifications.

Step 5: Reassemble the Inlet

1. Install the Inlet Components:
   • Place the seat, ball, and cage in the inlet housing.
2. Tighten the Inlet: Ensure this assembly is securely torqued as per the manual.

Step 6: Testing the Rebuilt Pump

1. Attach the Pump to a Machine: Connect the pump to a testing machine.
2. Run the Pump: Increase the pressure to around 3000 psi and observe for stability.
3. Check for Leaks: If the pump experiences pressure drop, it may indicate bypass material or worn components.

Conclusion

Rebuilding a Graco pump involves careful assembly and attention to torque specifications. Following these steps ensures a successful rebuild, but always refer back to the manual for specific torque ratings and components. If issues arise during testing, disassemble and inspect components for wear. Happy rebuilding!