TK370 Wheel Feller Buncher, TK380 Wheel Feller Buncher, TK371 Industrial Tractor and TK381 Industrial Tractor Machine Systems Caterpillar

Before you start the test procedure, perform the following procedure that is listed in the reference.

Reference: Refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.

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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.

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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.

Test

Illustration 1	g00909928
Pilot Oil Accumulator

The pilot oil accumulator is located on the right side of the machine.

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Illustration 2	g00993017

1. Remove the cover from the left side of the machine.

2. Repeat Step 1 on the right side of the machine.

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Illustration 3	g00993020

3. Remove two wing nuts (2) and screen assembly (1).

4. Repeat Step 3 on the other side of the machine.

5. Remove four bolts (4) and cover (3) .

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Illustration 4	g00864383
(5) Pressure tap (pilot oil accumulator).

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Illustration 5	g00906536
(6) Pressure tap (pilot supply pressure) (PS2) .

Note: The pressure tap is number four from the top of the combination valve.

6. Connect the Tooling that is listed in Table 1 to pressure taps (5) and (6) .

7. Start the engine. Move the hydraulic control lever lock to the UNLOCKED position.

8. Ensure that the oil in the hydraulic system is at normal operating temperature.

9. Check pilot supply pressure at pressure tap (6). The pilot supply pressure should be 2586 + 170 kPa - 70 kPa (375 + 25 psi - 10 psi).

   Reference: See the following reference if you need to adjust the pilot supply pressure.Testing and Adjusting, "Pilot System Pressure - Test".

10. Raise the lift arms.

11. Move the hydraulic control lever lock to the LOCKED position. Shut off the engine.

12. Observe the pressure at pressure tap (5) with the pressure gauge. After the engine is shut off, the pressure should decline rapidly to the accumulator charge pressure. Then, the pressure should remain steady, until the pilot supply in the accumulator is exhausted.

13. If the accumulator charge pressure is below 690 kPa (100 psi), replace the accumulator.

Charge

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Dry nitrogen is the only gas approved for use in the accumulators. The charging of oxygen gas in an accumulator will cause an explosion. An explosion can be eliminated by using nitrogen gas cylinders with standard CGA (Compressed Gas Association, Inc.) No. 580 connectors. When nitrogen gas is ordered, make sure to order the cylinders with CGA No. 580 connectors. Do not rely on color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders. In any application, never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity).

A new accumulator should be charged before installation. Do not charge an accumulator that is connected to a hydraulic system. Pressure from the hydraulic oil in the system may interfere with the charging procedure.

Gas pressure is variable with the temperature. The accumulator must be at the same temperature as the surrounding air before the accumulator can be charged. Use the following chart for the correct nitrogen charge. Use dry nitrogen.

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Illustration 6	g00281220
Nitrogen charging apparatus (1) Pressure gauge (2) Connection to nitrogen cylinder valve (3) Regulator assembly (4) Valve (5) Pressure gauge (6) Pressure regulating screw (7) Valve handle (8) Chuck

1. Connect the nitrogen charging apparatus to the nitrogen cylinder at fitting (2) .

2. Open the valve on the nitrogen cylinder.

3. Close valve (4) .

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Illustration 7	g00864447

4. Remove the cap from valve (9) of accumulator (10) .

5. Install chuck (8) on valve (9) of the accumulator. Open valve handle (7) on chuck (8). Use gauge (5) to monitor the nitrogen charge in the accumulator.

6. Check the temperature of the air around the accumulator. Refer to Table 3 for the correct charging pressure.

7. Open the valve on the nitrogen cylinder. Adjust screw (6) on the regulator assembly until gauge (1) is at the pressure that will charge the accumulator.

8. When the pressures on gauge (5) and on gauge (1) are identical, turn off valve (4) .

9. If the pressure on gauge (5) decreases, open valve (4) .

10. Repeat Steps 8 and 9 until you have the following results:
    • Pressure readings on gauge (5) and on gauge (1) are identical.

    • Pressure readings do not change.

11. Close the valve on the nitrogen cylinder.

12. Close valve handle (7) on chuck (8) .

13. Remove chuck (8) from valve (9) of the accumulator. Install the cap on valve (9) of the accumulator.

14. Install the pilot oil accumulator onto the machine.

15. Proceed to the "Test" section.