345C MHPU Mobile Hydraulic Power Unit Caterpillar

Disconnect the Hydraulics

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At operating temperature, the hydraulic oil is hot and under pressure. Hot oils can cause burns. To prevent possible personal injury, release the pressure in the work tool hydraulic circuit (boom, stick, bucket, and swing), travel circuits, and the hydraulic oil tank at the filler cap before any hydraulic lines or components are disconnected or removed. Remove the filler cap only when the engine is stopped and the filler cap is cool enough to touch.

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Illustration 1	g00887079

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Illustration 2	g01092530
(1) Support stand (2) Support bar (3) Lock pins

1. Place the storage stand (1) on ground that is level and solid. The open side of the stand must be oriented opposite the machine. Install support bar (2) in the open position. Lock the support bar in the open position with lock pin (3) .

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Illustration 3	g01100601
Stick cylinder is completely extended.

2. Before this procedure is performed the fore boom cylinder and the stick cylinder must be completely retracted. In the Ultrahigh Demolition Configuration, the work tool cylinder is completely extended.

3. Position the machine in front of the storage stand (1). Position the boom (4) and the stick (5) as the boom (4) and the stick (5) are illustrated in Illustration 3. Lower the boom (4) until the stick (5) is positioned slightly above the ground and until the support bar (2) of the stand can be handled between the boom and the stick. The boom is positioned over the storage stand with a slight clearance.

4. Move the support bar (2) under the boom. Secure the support bar with the lock pins (3) .

5. Lower the boom until the stick (5) is positioned slightly against the ground and the boom is positioned over the storage stand. Extend the stick slightly until the stick (5) touches the ground with the two brackets.

6. Stop the engine and move all implement control levers and foot pedals in order to release the pressure in the hydraulic lines.

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Illustration 4	g01104873
Ultrahigh Demolition Configuration (6) Ball valves (7) Quick connector (8) Pilot coupling

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Illustration 5	g01104906
Retrofit Configuration (6) Ball valves (7) Quick connector (8) Pilot coupling

7. Close the four ball valves (6) .

8. Plug or cap the hydraulic hoses.

9. If the machine is equipped with the quick connector (7) use step 10 in order to disconnect the quick coupler arrangement. If the machine is equipped with the quick connect ball valve use step 11 in order to disconnect the quick coupler arrangement.

10. Disconnect the quick connectors (7) by using the following instructions.

    Note: After disconnection of the biggest ball valve, oil leakage of 87 cc (5.31 in³).

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    Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support. The swing lock (if equipped) must be engaged before service is started. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

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    Illustration 6	g01191314

    1. Pull back sleeve (9) .

    2. Unscrew the main sleeve (10) with the sleeve (9) in the back position.

    3. Release the sleeve (9) and continue to unscrew the main sleeve (10) until the sleeve is disconnected.

       Note: If the sleeve (9) will not unlock, turn the main sleeve (10) clockwise. This should allow the sleeve (9) to pull back.

    4. After disconnection, clean the surface and connect the dust cap with the coupling for the quick disconnect in order to protect the couplings from dirt and other foreign material.

11. Disconnect the quick connect ball valve by using the following instructions.

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    Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support. The swing lock (if equipped) must be engaged before service is started. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

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    Illustration 7	g01181520
    (11) Fixed ball valve (12) Mobile ball valve (13) Drain plug

    1. By using the levers, rotate the lever to the closed position for the fixed ball valve (11) and the mobile ball valve (12) .

       Note: The lever is located in the tool box.

    2. Remove bolts from the mobile ball valve (12) .

    3. Remove drain plugs (13) from the leakage oil port in order to recover the oil.

    4. Disconnect the ball valves.

    5. Place a cover plate on the fixed ball valve (11) and mobile ball valve (12) .

12. Disconnect the pilot lines by using the following instructions.

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    Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support. The swing lock (if equipped) must be engaged before service is started. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

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    Illustration 8	g01104192
    Location of pilot coupling (8)

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    Illustration 9	g01099856
    (A) Lever (B) Locking button (C) Mounted coupling (D) Hydraulic block group (E) Dust cover

    1. Firmly grasp lever (A) and press the locking button (B) .

    2. While you are holding the locking button (B), lift the lever (A) in order to disengage the roll pins from the cam curves.

       Note: During disconnection, firmly hold the lever (A) in order to prevent any reaction due to the internal working pressure.

    3. Remove the hydraulic block group (D) from the mounted coupling (C) .

    4. Place the hydraulic block group (D) on a suitable support in order to prevent contamination and damage.

    5. Close dust cover (E) on the mounted coupling (C) in order to prevent contamination of the hydraulic system.

13. Disconnect the grease lines that run from the boom foot to the boom nose.

14. Disconnect the electrical harness that runs from the boom foot to the boom nose.

Remove the Boom

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Illustration 10	g00887084
(1) Boom foot (2) Expandable pin

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Illustration 11	g00887141
(3) Bolt (4) Sleeve (5) Pin (6) Release bolt (7) Washer (8) Bolt

1. Remove the expandable pin (2) from the lower bores. Begin by raising the boom slightly so that no hydraulic force or machine weight pushes the boom downward against the boom support arrangement.

   Note: Cleanliness is important when you work with the expandable pin assembly. Before you begin, clean the exterior areas around the expandable pin assemblies. Cleaning the exterior will help prevent foreign materials from entering the pin bores.

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Illustration 12	g00887143
(3) Bolt (7) Washer (8) Bolt

2. Remove four bolts (3). Remove bolt (8).

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Illustration 13	g00887232

3. Remove washer (7) .

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Illustration 14	g00887234

4. Turn the washer (7) in the opposite direction.

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Illustration 15	g00887149
(3) Bolt (6) Release bolt (7) Washer

5. Install washer (7) and install four bolts (3). Release the remaining pressure on the expandable pin by moving the boom slowly. Tighten the bolts alternately to a torque value of approximately 50 N·m (37 lb ft).

6. Install the release bolt (6) .

7. Repeat Steps 2 to 5 for the opposite side of the expandable pin.

8. Start the engine.

9. While the operator moves the boom up and down, strike bolt (6) with a sledge hammer. Striking the bolt helps to loosen sleeve (4). Check the torque on bolts (3) after every two or three strikes. If necessary, tighten the bolts (3) to a torque value of 50 N·m (37 lb ft).

10. When the sleeves are loose, lower the boom. Remove bolt (6), bolts (3), and washer (7). Perform this step on each side of the pin.

11. Remove sleeves (4) from each side of the pin.

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Personal injury or death can result from lifting a heavy component. The heavy component can fall if using an incorrect hoist and/or sling or fastener to lift the load. Be sure the hoist and other devices have the correct lifting capacity to lift a heavy component. The approximate weight of the heavy component is given below.

Note: The expandable pin assembly weighs approximately 77.5 kg (171 lb). Use a suitable lifting sling as a choke on the pin. Attach the lifting sling to a hoist. Use the hoist and the lifting sling for supporting and maneuvering the pin.

12. Remove the expandable pin.

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Illustration 16	g01092813
Ultrahigh Demolition Configuration

13. Slowly lower the boom onto the support stand. Lower the boom until the boom foot disengages from the boom nose.

14. Move the machine away from the boom nose.

15. Install the chains (9) .