321B LCR Excavator Caterpillar

4000 Hour Oil Change Interval

A 4000 hour maintenance interval for hydraulic oil (change) is available. The extended interval requires S·O·S monitoring of the hydraulic oil. The interval for S·O·S monitoring is every 500 hours. The maintenance interval for the hydraulic oil filter is not changed. If S·O·S monitoring is not performed, the 2000 hour maintenance interval must be used.

Machines with hammers are not included in the 4000 hour 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 4000 hour maintenance interval. Machines that are used in severe conditions must use the interval in the Maintenance Interval Schedule.

Lubricants

Approved hydraulic oil must be used to obtain the 4000 hour hydraulic oil change. Refer to the list that follows for approved oils.

Caterpillar Hydraulic Oils

• Cat HYDO

• TDTO

• TDTO (TMS)

• DEO

• Biodegradable Hydraulic Oil (HEES)

• MTO

Commercial Oils

Diesel engine oils (Heavy Duty) with a minimum zinc content of 900 ppm can be used. Acceptable commercial oils are identified by the American Petroleum Institute trademark (API). Refer to the list that follows for acceptable types of hydraulic oils.

• CF

• CF-4

• CG-4

• CH-4

Note: Industrial hydraulic oils are not recommended for the hydraulic systems of Caterpillar machines. Industrial hydraulic oils are more likely to allow corrosion and Industrial hydraulic oils are more likely to allow excessive wear.

Drain the Tank

Illustration 1	g00102482

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

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Illustration 2	g00869343
(1) Bolts (2) Washers (3) Cover

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

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Illustration 3	g00101445

3. Clean the area thoroughly in order to prevent dirt from entering the screen cover and the fill/vent plug.

4. Relieve the internal pressure from the hydraulic tank by loosening the fill/vent plug. After the pressure is relieved, remove the fill/vent plug.

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Illustration 4	g00101627

5. The oil drain valve is located under the hydraulic tank.

6. Remove the hydraulic tank access cover that is located under the upper structure. This will allow access to the drain valve.

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Illustration 5	g00869353

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

7. Remove the oil drain valve plug.

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Illustration 6	g00293719

8. Install a swivel hose with clear plastic tubing in order to open the drain valve. Drain the oil into a suitable container.

9. Remove the swivel hose in order to close the drain valve.

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

11. Clean the drain plug. Install the drain plug.

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Illustration 7	g00872618

12. Open the access door that is located on the right side of the machine.

13. Clean the pump, the hydraulic lines, and the hydraulic tank.

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Illustration 8	g00869355

14. Remove the plug from the tube. Allow the oil to drain into a container.

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

16. Clean the plug. Install the plug and the O-ring into the drain port.

Clean the Screen

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Illustration 9	g00869364
(4) Bolts (5) Washers (6) Cover (7) Spring (8) Screen

1. Remove bolts (4), washers (5), and cover (6) .

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

   Note: Do not allow spring (7) to fall into the tank.

2. Remove spring (7) and screen (8) .

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

3. 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 10	g00873230
(9) O-ring seal (10) O-ring seal

4. Remove O-ring seal (9) from the screen.

5. Inspect O-ring seal (9) and O-ring seal (10). Replace the O-ring seals if wear or damage is evident.

6. Install O-ring seal (9) on screen (8) .

7. Install screen (8) and spring (7). Then install cover (6), washers (5), and bolts (4) .

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

Fill the Tank

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

2. Inspect the O-ring on the filler plug for damage. Replace the O-ring, if necessary. Clean the filler plug. Install the filler plug.

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Illustration 11	g00869421

3. Remove the pressure cap.

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Illustration 12	g00101462

4. Inspect the pressure cap. Clean the pressure cap. Replace the pressure cap if damage is evident.

5. Install the pressure cap.

Fill the Pump

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Illustration 13	g00869431
(1) Cover (2) Bolt (3) Plug

Note: Do not attempt to start the engine until the pump has been filled with hydraulic oil. Serious damage to the hydraulic components can result.

1. When the hydraulic oil has been replaced,the air must be removed from the hydraulic oil system. Use the following procedure to remove the air from the hydraulic oil system.

   1. While the engine is stopped, remove the vent plug, which is on the top of the pump. Do not install the vent plug until the pump is filled with hydraulic oil. After the pump is filled with hydraulic oil, tighten the vent plug. Start the engine. When the engine is at low idle, fully raise the boom. Hold the boom in this position.

   2. Stop the engine. Slowly lower the boom until the bucket is on the ground. This pressurizes the hydraulic tank.

   3. Slowly loosen the vent plug for several turns until the hydraulic oil flows out of the opening for the vent plug. This indicates that the air has been released from the pump. Tighten the plug.

2. Close the access door.

3. Start the engine. Operate the engine at idling speed for five minutes.

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Illustration 14	g00102482

4. Operate the control levers 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.

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Illustration 15	g00869442
(A) High Temperature Range (B) Low Temperature Range

5. Maintain the oil level between the marks on the sight gauge in the appropriate temperature range.