CYLINDER HEAD GP 4677546 - Caterpillar

Illustration 3 g03774338
Main control valve
(3) Main relief valve
(4) Line relief valve for the stick cylinder rod end
(5) Line relief valve for the boom cylinder head end
(6) Line relief valve for the stick cylinder head end
(7) Line relief valve for the boom cylinder rod end
Start the engine.
Place the hydraulic activation control lever in the UNLOCKED position.
Place the machine controls at the following settings: engine speed dial "10" and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Move the joystick for the stick until the stick is at the full STICK OUT position (full retraction of the stick cylinder).
Check the main relief valve pressure setting at pressure tap (1) or pressure tap (2). The main relief valve pressure setting should be 30500 500 kPa (4423 73 psi).
Illustration 4 g03322302
Main relief valve (standard)
(A) Adjustment screw
(L) Locknut
Loosen the locknut. Set the temporary main relief pressure to 32000 500 kPa (4641 73 psi). Tighten the locknut. Note: Turn the adjustment screw clockwise in order to increase the pressure. Turn the adjustment screw counterclockwise in order to decrease the pressure.Note: Always make final pressure adjustments on pressure rise.
Verify the temporary main relief pressure setting with a second function. Move the joystick for the boom until the boom is at the full BOOM RAISE position (full extension of the boom cylinder). The main relief pressure should be 32000 500 kPa (4641 73 psi).
Mark the original position of the line relief for the boom cylinder head end (5).
Move the joystick for the boom until the boom is at the full BOOM RAISE position (full extension of boom cylinders).
Check the pressure setting of the line relief valve for the boom cylinder head end (5).
Loosen the locknut of the boom line relief valve (5). Turn adjustment screw of the boom line relief valve until the pressure reading at pressure tap (1) is 30000 kPa (4351 psi).
Move the joystick for the boom until the boom is at the full BOOM RAISE position (full extension of boom cylinders).
Check the pressure setting of the line relief valve for the boom cylinder head end (5).
Turn the adjustment screw of the boom line relief valve until the pressure reading at pressure tap (1) is 32000 500 kPa (4641 73 psi). Note: Always make final pressure adjustments on the pressure rise.Note: In order to prevent over setting, the adjustment should be stopped immediately after the pressure becomes within specification.
Repeat Step 9 to Step 15 for the following line relief valves:
Line relief valve for stick cylinder head end
Line relief valve for stick cylinder rod end
Line relief valve for boom cylinder rod end
Reset main relief valve pressure setting to the normal operating condition after the completion of the line relief test and adjust. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust". Bucket Cylinder Rod End and Bucket Cylinder Head End
Note: A continuous relief of the valve