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 work tools have been lowered to the ground, and the 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.

Note: Use the information in the reference to prepare the machine for this test. Also, use the information in the reference to relieve any system pressure that may be present in the hydraulic system.

Reference: For the correct procedure to prepare the machine for this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.

Reference: For the correct procedure to relieve any hydraulic oil pressure that may be present in the hydraulic system, refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the machine that is being serviced.

Use the following procedures to purge air from the main hydraulic system and the pilot hydraulic system.

Main Hydraulic System

There are several opportunities for air to enter the main hydraulic system.

• Filling a hydraulic tank after the tank has been drained.

• Filling a hydraulic tank after a hydraulic line has been removed.

• A hydraulic component is replaced or removed.

• Any portion of the hydraulic system is opened.

If air is trapped in the system the following conditions may exist.

• Irregular movement of the cylinders

• The implement controls do not respond.

• Intermittent motion of implements

To resolve this problem, use the following procedure to remove the air from the hydraulic system.

1. Release all hydraulic system pressure. Refer to the reference at the beginning of this procedure.

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Illustration 1	g00829052
(1) Upper hydraulic implement pump. (2) Case drain line.

2. Remove case drain line (2) on upper hydraulic implement pump (1).

3. Fill the case with oil until oil seeps out of the case.

4. Install case drain line (2) .

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Illustration 2	g00785897
(3) Air purge plug. (4) Swing motor.

5. Slightly crack air purge plug (3) on swing motor (4). All of the air has been purged when oil seeps out of air purge plug (3) .

6. Tighten air purge plug (3) .

7. Wait for approximately four minutes in order to allow the air to rise out of the hydraulic system.

8. Start the engine.

9. Cycle all implements through the full range of motion. Cycle the implements several times.

   Note: Cycling cylinders and other implements should force trapped air out of the main hydraulic system.

10. Wait for approximately four minutes in order to allow the air to rise out of the hydraulic oil.

11. Check the hydraulic fluid level after you actuate any cylinders or motors. Top off the fluid level, if necessary.

Pilot Hydraulic System

Air can be trapped in the pilot hydraulic system. Air that is trapped in the pilot hydraulic system may shift a control valve spool. If a control valve spool is shifted, the corresponding implement could move. Trapped air can also be responsible for cylinder drift.

If the pilot hydraulic system has been opened, follow the procedure to release any air that is trapped in the pilot hydraulic system.

Note: Most of the air should work out of the system when all of the implements are cycled. If air remains in the system, follow the procedure below in order to release the air.

Main Hydraulic Circuit

1. Shut off the engine.

2. Release all hydraulic system pressure. Refer to the reference at the beginning of this procedure.

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Illustration 3	g00785903
Air Purge Plugs for Pilot System (5) Main control valve (top view).

3. The following valves are part of main control valve (5), right track, left track, tool tilt, swing, boom, and stick.

   Note: The air purge plugs are located on both ends on the control valves.

4. Slightly crack the air purge screw for the implement that does not function correctly. Keep the air purge screw cracked until a small amount of oil seeps out of the purge screw.

5. Tighten the air purge screw.

Felling Head

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Illustration 4	g00829129
(6) Control valve (felling head).

1. The following valves are part of control valve (6), grapple arms, collector arms, and lateral tilt.

   Note: The air purge plugs are located on both ends on the control valves.

2. Slightly crack the air purge screw for the implement that does not function correctly. Keep the air purge screw cracked until a small amount of oil seeps out of the purge screw.

3. Tighten the air purge screw.