BEARING 4J6678 - Caterpillar

The high pressure relief valves for this pump are a non-adjustable, cartridge type. When the pressure reaches the relief valve setting, oil acts on the poppet and is channeled into the low pressure side of the system. These relief valves can be more efficiently tested by using the 1U-8900 Cartridge Relief Valve Tester with the 1U-9358 Cartridge Relief Valve Manifold. For further information, see NEHT6031 Cartridge Relief Valve Test Procedure.1. Adjust charge pressure from auxiliary pump to 1700 kPa (250 psi). Open flow regulating valve to a flow rate of approximately 19 lpm (5 gpm).2. Increase pump rotation to 1000 rpm. 3. Slowly increase signal pressure to pump control port (4, Figure 2) to 300 100 kPa (44 15 psi) . Record pump output flow at this point. Pump output should be 7.8 1.0 lpm (2.0 .3 gpm).4. Slowly increase pump load to 42000 2100 kPa (6100 300 psi).5. When pump reaches this load point, output flow will decrease to 1.0 0.4 lpm (.25 .10 gpm). 6. If pressure continues to increase above this point, stop test and replace the relief valve.7. Repeat test for opposite pump output.8. Reduce signal pressure and repeat Step 5.