VALVE GP-CONTROL 3549539 - Caterpillar

Operation Checks
When checks are made while the machine is in operation, make sure only one operator is on the machine. Keep other personnel away from the machine. Make sure checks are done in a flat and open area.
The operation checks can be used to find leakage in the system. They can also be used to find a bad valve or pump. The speed of rod movement when the cylinders operate can be used to check the condition of the cylinders and the pump.1. Watch the cylinders as they are extended and retracted. Movement must be smooth and regular.2. Listen for noise from the pump.Operate the machine in each direction and in all speeds. Make note of all noises that are not normal and find their sources. If the operation is not correct, make reference to the CHECK LIST DURING OPERATION for "problems" and "probable causes."Check List During Operation
PROBLEM: Noise from the pump. PROBABLE CAUSE:1. Low oil level in the tank.2. Air in the hydraulic system.3. Oil is the wrong viscosity.4. Oil is cold. PROBLEM: Pump gets too hot. PROBABLE CAUSE:1. Oil leakage inside pump.2. Low oil level in the tank. PROBLEM: Oil pressure in the system is too low. PROBABLE CAUSE:1. Compensator valve on the pump needs adjustment.2. Loss of oil inside pump for too much movement (slippage).Implement Hydraulic System Testing And Adjusting
Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, do the procedure that follows before testing and adjusting the hydraulic system:
1. Move the machine to a smooth horizontal location. Move away from working machines and personnel and lower all implements to the ground.2. Permit only one operator on the machine. Keep all other personnel either away from the machine or in view of the operator.3. Move the hydraulic control levers to all positions to release the pressure in the hydraulic system.4. Carefully loosen the filler cap on the hydraulic tank to release the pressure in the tank.5. Make sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened, removed or adjusted.6. Tighten the filler cap on the hydraulic tank.7. The pressure in the system has now been released and lines or components can be removed.During a diagnosis of the hydraulic system, remember that correct oil flow and pressure are necessary for correct operation. Oil pressure is caused by resistance to the flow of oil.Visual checks and measurements are the first step when troubleshooting a possible problem. Then do the Operation Checks and last the Instrument Tests.Use the 5S5123 and 6V4161 Hydraulic Test Groups. If the basic tests give an indication of circuit leakage, install a flow meter and do a system test. This procedure will find the source of the leakage.Checking Pump Efficiency
For any pump test, the pump flow, measured in U.S. gpm (liter/min) at 100 psi (690 kpa) will be larger than the pump flow at 1000 psi (6900 kPa) at the same rpm.The