323F Excavator Hydraulic System Oil Filter (Return) - Replace Caterpillar

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

The return filter is a cartridge type filter. The amount of foreign material that enters the hydraulic system is reduced when the filter element is replaced.

Two different filters are available for the return filter. One filter is used for standard applications such as digging and normal use of a hammer. The second filter is used for an application such as demolishing a ceiling in a tunnel with a hammer.

Note: If the message display shows that the hydraulic return filter is plugged, turn off the machine. After you make sure that the warning has disappeared, start the machine and run the machine on level ground for approximately 10 minutes. If the warning still appears in the message display, inspect the filter and replace the filter, if necessary.

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Illustration 1	g06018342

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

2. Clean the area thoroughly in order to keep dirt out of the return filter. 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.

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   Illustration 2	g02275615
   Filler cap (A) LOCK position (B) PRESSURE RELEASE - START position (C) PRESSURE RELEASE - END position (D) OPEN position

3. Release the pressure that may be present in the return hydraulic circuit with the following procedure. Refer to Illustration 2 for filler cap positions.

   1. Turn the filler cap counterclockwise and move the arrow from position (A) to position (B).

   2. Release the pressure for a minimum of 45 seconds by moving the arrow from position (B) to position (C).

   3. Push the filler cap down and move the arrow from position (C) to position (D).

   4. After the tank pressure is relieved, tighten the filler cap on the hydraulic tank to position (A).

4. Check the hydraulic system oil level.

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

5. Remove the filter cartridge. Perform the following steps in order to remove the filter cartridge.
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   Illustration 3	g00102211
   (1) Bolts (2) Washers (3) Cover (4) Plug (5) Filter cartridge

   1. Remove bolts (1), washers (2), and cover (3).

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

   2. Remove plug (4) in order to release the pressure in filter cartridge (5).

      Note: When plug (4) is removed the oil level in the return filter drops to the level of the hydraulic tank.

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      Illustration 4	g02515262
      (5) Filter cartridge (6) Filter case (E) Guide

   3. Pull up the handle at the top of filter cartridge (5) until the filter cartridge contacts guide (E) on filter case (6).
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      Illustration 5	g00102214

   4. Turn the filter cartridge counterclockwise by 180 degrees in order to align the projection of the filter cartridge with the notch of the filter case. Pull out the filter cartridge.
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      Illustration 6	g00102219
      (7) O-ring

   5. Inspect the cover and O-ring (7). If either part is damaged, replace the part.

   6. Inspect the filter cartridge for debris and for damage. If necessary, replace the filter cartridge.

6. Remove the filter element. Perform Step 6.a through Step 6.f in order to remove the filter element.
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   Illustration 7	g00104507
   (4) Plug (8) Plate (18) O-ring

   1. Make sure that plug (4) is removed. Make sure that all of O-ring (18) is removed from plate (8).
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      Illustration 8	g00918893
      (8) Plate (9) Spiral retaining ring

   2. Remove spiral retaining ring (9).
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      Illustration 9	g00104510
      (8) Plate (10) Shell (11) O-ring (12) Filter element

   3. Hold the filter cartridge with one hand. Grasp the grip of plate (8) with your other hand. Lift plate (8) in order to separate plate (8) from the filter cartridge.

   4. Remove O-ring (11) from plate (8).

   5. Lift filter element (12) from shell (10).

   6. Pour the remaining oil into a suitable container.

      Note: Dispose of used oil according to local regulations.

   7. Repeat Step 6.a through Step 6.f for the other filter groups.

7. Clean the shell of the filter cartridge. Perform Step 7.a through Step 7.d in order to clean the shell of the filter cartridge.
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   Illustration 10	g00104511
   (13) Slide plate (14) Pads (15) Screws (19) Port

   1. Turn shell (10) upside-down.

   2. Remove screws (15).

   3. Remove Pads (14) from slide plate (13).

   4. Wash the following parts in a clean nonflammable solvent: plug (4), plate (8), spiral retaining ring (9), shell (10) and Pads (14). Dry the parts.

8. Install the filter elements. Perform Step 8.a through Step 8.k in order to install the filter elements.

   Note: Consult a AVSpare dealer for the Service Kit that is needed to install the filter element and the filter cartridge.

   1. Apply spray type oil to the inside of shell (10) in order to prevent rust.

   2. Apply grease to a new O-ring (11).

   3. Plate (8) will contact the inside of shell (10). Apply grease to this point.

   4. Apply grease to O-rings inside ports (19) at the bottom of shell (10).

   5. Install new Pads (14). Tighten the screws to a torque of 0.4 N·m (3.5 lb in).

   6. Apply spray type oil into the clearance between shell (10) and slide plate (13).
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      Illustration 11	g00104512
      (8) Plate (10) Shell (16) Boss (17) Notch

   7. Turn over shell (10). Apply grease to the two O-rings on new element (12). Install element (12) into shell (10).

   8. Move boss (16) in alignment with notch (17). Install plate (8) into shell (10).

   9. Install spiral retaining ring (9) into the groove in shell (10).

   10. Apply grease to new O-ring (18). Install O-ring (18) on plug (4).

   11. Install plug (4) into plate (8).

9. Install the filter cartridge. Perform Step 9.a through Step 9.e in order to install the filter cartridge.
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   Illustration 12	g02515259
   (F) Port (G) Slide plate

   1. Check that ports (F) at the bottom of the filter case are closed.

      Note: If the ports are open, rotate slide plate (G) counterclockwise to the stopper in order to fully close the ports. When the ports are fully closed, any remaining oil in the filter case should be completely removed.

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      Illustration 13	g02515258
      (I) Slide plate (H) Port

   2. Check that ports (H) of the filter cartridge are fully closed.

      Note: The filter cartridge cannot be installed unless the ports are fully closed. If the ports are open, rotate slide plate (I) counterclockwise to the stopper in order to fully close the ports.

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      Illustration 14	g02515257
      (J) O-rings

   3. Check that O-rings (J) have been installed and that oil has been applied to O-rings (J).
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      Illustration 15	g00102225
      (1) Bolts

   4. Install the filter cartridge into the filter case. Turn the filter cartridge clockwise by 180 degrees and push down the filter cartridge when the filter cartridge contacts guide (E).

   5. Install plug (4), cover (3), washers (2), and bolts (1). Tighten bolts (1) to a torque of 29 ± 5 N·m (22 ± 4 lb ft).

10. Check the hydraulic system oil level.

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