521B and 522B Track Feller Bunchers Caterpillar

Hydraulic System Oil - Change

Usage:

521B F7B

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids. Dispose of all fluids according to local regulations and mandates.

Operate the machine for a few minutes to warm the hydraulic system oil.

Open the hood. Refer to Operation and Maintenance Manual, "Hood Tilt" for the procedure.

Park the machine on level ground. Shut off the engine.

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Illustration 1	g01054199

Press the hydraulic tank breaker relief valve to relieve any tank pressure.

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Illustration 2	g01050435
Bottom View of the Machine (1) Plug.

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

Remove plug (1) from the bottom of the hydraulic tank. Wash the drain plug in a clean, nonflammable solvent.

The hydraulic tank is equipped with an ecology drain valve. Attach a hose to a 126-7914 Oil Drain Coupling. Install the threaded end of the coupling into the drain valve to unseat the internal drain valve.

Drain the hydraulic oil into a suitable container.

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NOTICE

Never start the engine while the hydraulic oil tank is being drained or while the hydraulic oil tank is empty. Excessive wear and damage to the hydraulic components can occur.

After the oil has been drained, tighten the drain plug to a torque of 68 ± 7 N·m (50 ± 5 lb ft).

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

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Illustration 3	g01055387
(2) Plate.

A strainer is located behind plate (2). Remove four bolts and washers to remove the plate. Remove the strainer.

Wash the strainer in clean, nonflammable solvent. Inspect the strainer for damage. Replace the strainer if the strainer is damaged.

Install the strainer.

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Illustration 4	g01050447
(3) Electric pump. (4) Filler tube. (5) Switch.

Fill the hydraulic oil tank. Use electric pump (3) to fill the hydraulic tank. Use the following procedure to fill the hydraulic system. Refer to Operations and Maintenance Manual, "Refill Capacities" for the refill capacity of the hydraulic system.

Note: Make no attempt to start the engine until the pump has been filled with hydraulic oil. Serious damage to the hydraulic components can result.

Remove tube assembly (4).
Place tube assembly (4) in a new container of hydraulic oil.
Move switch (5) for pump (3) to the ON position.
Fill the tank.
Move switch (5) to the OFF position and place tube assembly (4) in the holder, when the hydraulic system has been filled.

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Illustration 5	g01050793
Main Pump (6) Plug. (7) Plug.

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 14.a through Step 14.g.

While the engine is stopped, remove air purge plug (7). Fill the pump with oil. Do not install air purge plug (7) until the pump is filled with hydraulic oil.
After the pump has been filled with oil, install air purge plug (7).
Remove air purge plug (6). Pour oil into the pump until oil comes out of the port. Install air purge plug (6).
Start the engine. When the engine is at low idle, fully raise the boom. Hold the boom in this position.
Stop the engine. Slowly lower the boom until the felling head is on the ground. This pressurizes the hydraulic tank.
Slowly loosen air purge plug (6) until the hydraulic oil flows out of the opening. This indicates that the air has been released from the pump.
Tighten air purge plug (6).

Start the engine. Operate the engine at idling speed for 5 minutes.

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