Lowering the Boom With the Engine Stopped - Standard on Machines
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When lowering the boom with the engine stopped, keep all personnel away from the boom area. The boom vent valve must be closed before the machine is operated. |
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- 1. Unlatch and open the front access door on the left side.
- 2. Rotate 6.35 mm (.25 inch) square stem located on boom vent valve counterclockwise to manually open vent. Boom will start to lower as valve is opened.
- 3. Manual vent valve stem must be fully closed for normal operation. Close the access door.
Lowering the Boom With the Engine Stopped - If Equipped With Boom Cylinder Mounted Check Valve
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When lowering the boom with the engine stopped, keep all presonnel away from the boom area. The boom vent valve must be closed before the machine is operated. |
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Valves must be opened in proper sequence. They must be fully closed for normal operation.
- 1. Open vent valves located in check valves mounted on each boom cylinder by rotating the 6.35 mm (.25 inch) square stems counterclockwise all the way.
- 2. Unlatch and open the front access door on the left side.
- 3. Open boom vent valve located in main valve compartment by rotating 6.35 mm (.25 inch) square stem counterclockwise. Boom will start to lower as valve is opened.
- 4. Manual vent valve stems must be fully closed for normal operation.
- 5. Close access door.
Raising Boom With Engine Stopped
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When working around or under a raised boom, block or secure the boom in position. Before attempting to operate the machine, be sure to reconnect all lines. |
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- 1. A boom cylinder bleed screw is located in a junction block in the upper structure, below the boom pivot.
- 2. Open the bleed screw to relieve residual pressure in the hydraulic lines.
- 3. Disconnect one of the center hose assemblies that is connected to the rod end of the boom cylinders.
- 4. Close the bleed screw.
- 5. An external lifting device can then be used to lift the bucket to ground level.
- 6. Secure or block the boom.
- 7. Connect the hydraulic hose assembly.
- 8. Refer to "Towing" if the machine must be towed away from the excavation.
To Swing Machine with Engine Stopped
- 1. Apply the swing brake (upper position).
- 2. Disconnect the two swing motor lines inside the front of the upper structure.
- 3. Attach an external lifting device to the bucket (see "Raising the Boom With the Engine Stopped"). Raise the bucket to ground level.
- 4. Release the swing brake (lower position).
- 5. Lift and swing the boom away from the excavation.
- 6. Apply the swing brake.
- 7. Before starting repairs, lower, block or secure the boom.
- 8. Connect the hydraulic lines to the swing motor.
Broken or Ruptured Lines
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Do not activate the controls for any circuit that has been blocked out. Do not use a blocking plate in a line that connects a pump to a control valve. To ensure a line has sufficient burst capacity, use the correct AVSpare Part Number part as a replacement. |
If a machine must be moved with a broken or ruptured line in any circuit, other than the track circuit, install a blocking plate. Install it on the upstream side (the side coming from the oil supply) of the break in the line.
This will block the oil flow and allow the machine to be moved under its own power.
Keep the blocking plates in the machine tool box when not in use.