336E Excavator and 336E MHPU Mobile Hydraulic Power Unit Machine Systems Boom Cylinder - Remove and Install Caterpillar

Removal Procedure

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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Cylinders equipped with lock valves can remain pressurized for very long periods of time, even with the hoses removed. Failure to relieve pressure before removing a lock valve or disassembling a cylinder can result in personal injury or death. Ensure all pressure is relieved before removing a lock valve or disassembling a cylinder.

1. Fully extend the bucket cylinder. Fully extend the stick cylinder. Lower the boom until the stick assembly is in contact with the ground.

2. Release the pressure in the hydraulic system.
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   Illustration 1	g02138737

3. Install Tooling (A) onto the hydraulic tank. Attach an air supply hose onto Tooling (A). Apply 276 kPa to 414 kPa (40 psi to 60 psi) of air. This procedure will pull vacuum on the hydraulic system.
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   Illustration 2	g00574959

4. Disconnect hose assembly (1).
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   Illustration 3	g00574971

5. Attach a suitable lifting device to boom cylinder (4). The weight of boom cylinder (4) is approximately 380 kg (838 lb).

6. Remove bolts (2), plate (3), and the spacer.
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   Illustration 4	g01204569

7. Install Tooling (B) in pin (5). Use a hammer to drive pin (5) out of boom cylinder (4). Use the suitable lifting device to lower boom cylinder (4).
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   Illustration 5	g01204668

8. Loosen nut (6). Loosen seat (7).
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   Illustration 6	g01204652

9. Disconnect tube assembly (8).
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   Illustration 7	g01204669

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   Illustration 8	g01204674

10. Disconnect hose assembly (13) and hose assemblies (12). Disconnect tube assemblies (11) and (14).

11. Remove support assembly (15) from boom cylinder (4). Attach a suitable lifting device to boom cylinder (4). The weight of boom cylinder (4) is approximately 380 kg (838 lb). Remove bolt (9), pin assembly (10), and boom cylinder (4).

Installation Procedure

1. Install boom cylinder (4) in the reverse order of removal.

   1. Lubricate pin assembly (10) with Tooling (C).

   2. Tighten nut (6) to a torque of 4 N·m (35 lb in).

   3. Tighten seat (7) to a torque of 2 N·m (18 lb in).

   4. Lubricate pin (5) with Tooling (C).

Disassembly and Assembly

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When you are using hydraulic cylinders and puller studs, always ensure that the rated capacity of the puller stud meets or exceeds the rated capacity of the hydraulic cylinder. If the puller stud does not meet or exceed the rated capacity of the hydraulic cylinder, a sudden failure of the puller stud could occur. The sudden failure of the puller stud could result in personal injury or death.

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Cylinders equipped with lock valves can remain pressurized for very long periods of time, even with the hoses removed. Failure to relieve pressure before removing a lock valve or disassembling a cylinder can result in personal injury or death. Ensure all pressure is relieved before removing a lock valve or disassembling a cylinder.

Illustration 9	g06012759

(1) Tooling (J) is used for the removal and installation of the bearing.

(2) Lubricate the threads and the face of piston (2). Tighten piston (2) to a torque of 11000 ± 550 N·m (8110 ± 405 lb ft).

(2A) Tighten to a torque of 300 ± 30 N·m (221 ± 22 lb ft). Turn bolts (2A) an additional 30 ± 5 degrees.

(3) Tooling (H) is used for the removal and installation of the bearing.

(4) Apply Tooling (G) to the threads of setscrews (4). Tighten setscrews (4) to a torque of 50 ± 10 N·m (37 ± 7 lb ft).

(5) Apply Tooling (F) to inner diameter and the outer diameter of seals (4).

(6) The slit of ring must be in the direction of piston.

(7) Lubricate the sealing lip with lubricant that is being sealed.

(8) Apply Tooling (E) to the wiper seal groove prior to assembly. Lubricate the sealing lip with lubricant that is being sealed.