323F Excavator Hydraulic System Oil - Change Caterpillar

Cat HYDO Advanced 10 Oil Change Interval

The standard Cat HYDO Advanced 10 oil change interval is every 6000 service hours or 3 years.

But a 6000 service hour or 3-year maintenance interval for hydraulic oil (change) is recommended with S·O·S monitoring of the hydraulic oil after 3000 service hours. The interval for S·O·S monitoring is every 500 hours. The Oil change is recommended when the oil deterioration or contamination is detected. The maintenance interval for the hydraulic oil filter is not changed.

Machines with hammers are not included in the 6000 service hour or 3-year maintenance interval. Machines with hammers must use the intervals that are listed in the Maintenance Interval Schedule. Machines that are used in severe conditions are not included in the 6000 service hour or 3-year maintenance interval. Machines that are used in severe conditions must use the interval in the Maintenance Interval Schedule.

Procedure to Change the Hydraulic Oil

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Illustration 1	g02022844

1. Park the machine on level ground. Lower the bucket to the ground so that the stick is vertical.

2. Open the engine access cover.
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   Illustration 2	g06018342

3. Remove bolts (1), washers (2), and cover (3) from the top of the hydraulic tank.
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   Illustration 3	g02243876

4. Clean the area thoroughly in order to keep dirt out of the screen cover. Clean the area thoroughly in order to keep dirt out of the filler cap.
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   Pressurized system! The hydraulic tank contains hot oil under pressure. To prevent burns from the sudden release of hot oil, relieve the tank pressure with the engine off by slowly turning the cap approximately 1/8 of a turn until the cap reaches the secondary stop.

5. Relieve the internal pressure from the hydraulic tank by slowly turning the tank cap approximately 1/8 of a turn until the cap reaches the secondary stop. After the tank pressure is relieved, then push down on the cap and continue turning until the cap can be removed.
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   Illustration 4	g02022853
   The oil drain valve is located under the hydraulic tank.

6. Remove the hydraulic tank access cover that is located under the upper structure. Removing the cover will allow access to the drain valve.
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   Illustration 5	g01124017
   (4) Plug

   Note: Refer to Operation and Maintenance Manual, "General Hazard Information" for information that pertains to containing fluid spillage.

7. Remove plug (4).

8. Inspect the O-ring. Replace the O-ring if wear or damage is evident.
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   Illustration 6	g01124018
   (5) Swivel hose (6) Drain plug

9. Install swivel hose (5) with clear plastic tubing.

10. Loosen drain plug (6) in order to drain the oil.

11. Drain the oil into a suitable container.

12. After the oil has been drained, tighten drain plug (7) to 110 ± 15 N·m (81 ± 11 lb ft).

13. Remove the swivel hose.

14. Clean plug (4) and install the plug. Tighten the plug to a 75 ± 5 N·m (55 ± 3.7 lb ft).

15. Open the access door on the right side of the machine.

16. Clean the pump, the hydraulic lines, and the hydraulic tank.
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    Illustration 7	g02144193

17. Remove plug (7) from the tube. Allow the oil to drain into a container.

    Note: Dispose of used filters and used fluids according to local regulations.

18. Inspect the O-ring. Replace the O-ring if wear or damage is evident.

19. Clean the plug. Install the plug and the O-ring into the drain port.
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    Illustration 8	g02243878
    (8) Bolts (9) Washers (10) Cover (11) Spring (12) Screen

20. Remove bolts (8), washers (9), and cover (10).

    Note: Dispose of used filters and used fluids according to local regulations.

    Note: Do not allow spring (11) to fall back into the tank.

21. Remove spring (11) and screen (12).

    Note: Refer to Operation and Maintenance Manual, "General Hazard Information" for information on containing fluid spillage.

22. Wash the screen in a clean nonflammable solvent. Allow the screen to dry. Inspect the screen. Replace the screen, if the screen is damaged.
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    Illustration 9	g02243880
    (13) O-ring seal (14) O-ring seal

23. Remove O-ring seal (13) from the screen.

24. Inspect O-ring seals (13) and (14). Replace the O-ring seals if wear or damage is evident.

25. Install O-ring seal (13) on screen (12).

26. Install screen (12) and spring (11). Then install cover (10), washers (9), and bolts (8).

    Note: Make sure that the O-ring seals and the spring are properly positioned during installation.

27. Fill the hydraulic system oil tank. Refer to Operation and Maintenance Manual, "Capacities (Refill)".

28. Inspect the O-ring seal on the filler cap for damage. Replace the O-ring, if necessary. Clean the filler cap. Install the filler cap.
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    NOTICE
    When the main hydraulic pump has been serviced or the hydraulic oil has been replaced, the air in the hydraulic system must be purged. Do not start the engine until the main hydraulic pump has been filled with oil. Operating the hydraulic pump without proper lubrication will damage the pump and other hydraulic components.

29. When the hydraulic oil has been replaced, the air must be removed from the hydraulic oil system. To remove the air from the hydraulic oil system, follow Step 29.a through Step 29.g.

    1. Access the hydraulic pump. The hydraulic pump is located behind the right side access door.
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       Illustration 10	g06226748
       (15) Drain hose (16) Connector (17) Fitting

    2. While the engine is stopped, remove drain hose (15) and connector (16) from the top of the pump. Add hydraulic oil through the opening.

       Note: Check the condition of the O-ring seals on connector (16). If the seals are damaged, replace the seals.

    3. After the pump has been filled with oil, install drain hose (15) and connector (16) to the original locations.

    4. Start the engine. When the engine is at low idle, fully raise the boom. Hold the boom in this position.

    5. Stop the engine and slowly lower the boom until the work tool is on the ground. The hydraulic tank will pressurize.

    6. Slowly loosen fitting (17) until the hydraulic oil flows out of the opening. This indicates that the air has been released from the pump.

    7. Tighten fitting (17).

30. Start the engine. Operate the engine at idling speed for 5 minutes.
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    Illustration 11	g02022844

31. Operate the joysticks in order to circulate the hydraulic oil. Lower the bucket to the ground so that the stick is vertical to the ground. Stop the engine.

32. Check the hydraulic oil level.

    Reference: For the correct procedure, refer to Operation and Maintenance Manual, "Hydraulic System Oil Level - Check".

33. Close the access door.

34. Close the engine hood and latch the engine hood.

Fast Fill

If your machine is equipped with a deluxe service center, you may drain the hydraulic oil through the fast fill port. You may also add the hydraulic oil through a fast fill port.

Illustration 12	g02710758

1. Remove the dust cover.

2. Attach the hose to the male coupling.

3. Drain the oil or add the oil, as needed.