TK1051 Track Feller Buncher Machine Systems Caterpillar

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

The correct oil temperature, flow, and pressure are necessary for correct operation. Pump output (oil flow) is a function of engine speed (rpm) and valve adjustment. Oil pressure is caused by resistance to the flow of oil.

The load sensing valves regulate the main hydraulic pumps.

The relief valves in the implement circuit, in the swing circuit and in the travel circuit protect the components from high pressures in the circuits when the control valves are activated.

The pilot oil is used to activate all implements, the swing, and the travel.

• The oil pressure for opening the relief valves must be within specifications. Pressures that are too low will cause a decrease in implement functions. Pressures that are too high will cause a decrease in the life of the hoses and of other components.

• Cylinder drift is caused by the following problems: leakage past cylinder pistons, leakage past the O-ring seals in the control valves and check valves that do not seat correctly. Poor adjustments of the control valves or incorrect fit may also contribute to circuit drift.

• Cycle times that are longer than normal result from oil leakage, from pump wear, or from the pump speed.

If the basic tests indicate a leak in the circuit, install a flow meter and perform a test. This procedure will help to find the source of a leak.

Problem 1: The pump makes noise and the cylinder rods do not move evenly. There are also air bubbles in the oil.

Probable causes:

1. The viscosity of the oil is incorrect.

2. The relief valve opens at low oil pressure.

3. There is a loose connection of the oil line on the inlet side of the pump.

4. The pump has too much wear.

Problem 2: The oil temperature is too high.

Probable causes:

1. The viscosity of the oil is incorrect.

2. The setting of the relief valve is too low. This causes the relief valve to open prematurely.

3. The pump has too much wear.

4. There is a restriction in an oil passage.

5. There is an oil leak in one of the circuits.

6. The load on the system is too high. This causes the relief valve to open.

7. The oil level is low.

8. There is a high pressure oil leak in one or more circuits.

9. The oil is contaminated.

10. There is air in the hydraulic oil.

    Note: A problem with air in the hydraulic oil must be corrected before the hydraulic system will operate at normal temperatures.

    There are two conditions that cause air to be in the hydraulic oil:

    1. Return oil flows into the hydraulic tank above the level of oil that is in the tank.

    2. There are oil leaks in the oil suction line between the pump and the tank.

Problem 3: The pump output is low.

Probable causes:

1. The oil level is low.

2. The viscosity of the oil is incorrect.

3. The pump has too much wear.

Problem 4: The oil pressure is low.

Probable causes:

1. The relief valve opens at low oil pressure.

2. The pump has too much wear.

3. An O-ring seal in the system failed.

4. The control valve and the valve spool have a large amount of wear.

Problem 5: The attachment moves while the control lever is in the HOLD position.

Probable causes:

1. The control valve and the valve spool have a large amount of wear.

2. A piston seal in a cylinder has a large amount of wear.

3. There is a leak in a connection between the control valve and the cylinders.

4. A check valve is not closing because of dirt or because of a worn seat.

5. The control valve is not centering correctly. This problem can be caused by a broken spring or a sticky valve spool.

6. There may be residual pilot pressure in the system.

Problem 6: The attachment droops when the control lever is actuated.

Probable causes:

1. The oil is too cold.

2. There is air in the signal network.

3. The piston seals and/or the lift cylinders are worn.

4. Advanced signal passages in the main spool of the control valve are blocked in the affected circuit.

5. The load check valve is not closing because the spring is weak or broken or because there is dirt or debris in the check valve.

Problem 7: Implement cycle times are too slow.

Probable causes:

1. A control valve spool is out of position.

2. The setting for the line relief valve for the affected circuit is too low.

3. The line relief valve for the affected circuit is leaking.

4. The flow control spring is broken.

5. The margin pressure setting is too low.

6. The flow limiter valves on the main control valve are set incorrectly.

7. The pilot relief valve is set too low.

8. The circuit for signal oil has internal leakage or internal blockage. Check the following causes for leakage or for blockage.

   1. The seals of the flow control valve are failing.

   2. The plug in the end of a control valve spool for an implement control valve is leaking.

Problem 8: Too much cylinder drift exists in one of the hydraulic circuits.

Probable causes:

1. The valve spool in the control valve is not correctly centered. A spring is broken. The control valve spool is sticking. The control linkage is not correctly adjusted.

2. Cylinder piston seals are failing in the affected circuit.

Problem 9: There is a pause before pressure is reached in all circuits. All implement functions are sluggish.

Probable causes:

1. There is air in the signal network.

2. The oil level is too low.

3. The implement pump is worn or damaged.

4. The control valve is sticking.

5. There is a leak in the signal network.

6. The pilot oil pressure is inconsistent.

Problem 10: The felling head tilts too fast, or the felling head tilts too slowly.

Probable causes:

1. The control valve's main spool is not fully shifted for the affected circuit.

2. There is a leak in the cylinder.

3. The flow limiter valves on the main control valve are set incorrectly.

4. The restrictor bolt needs to be replaced.

Problem 11: The disc saw speed is slow.

Probable causes:

1. The saw motor has too much wear.

2. The relief valve on the saw motor valve is set too low.

3. The control valve's main spool is not fully shifted for the affected circuit.

4. The saw pump has too much wear.

5. The maximum displacement of the saw pump is set too low.

6. The minimum displacement on the saw motor is set too high.