844K Wheel Dozer Machine Systems Caterpillar

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Do not operate or work on this machine or work tool unless you have read and understand the instructions and warnings in the Operation and Maintenance Manuals and Owner's Manuals. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Caterpillar dealer for replacement manuals. Proper care is your responsibility.

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Diesel engine exhaust contains products of combustion which may cause personal injury. Always start and operate the engine in a well ventilated area, and, if in an enclosed area, vent the exhaust to the outside.

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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 attachments have been lowered, 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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Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

A visual inspection of the propulsion system and the propulsion system components is the first step when a diagnosis of a problem is made. Stop the engine, and make the following inspections.

1. Measure the oil level in the hydraulic oil tank.

2. Use a clear container to obtain an oil sample from the hydraulic tank immediately after the engine is stopped. Examine the sample for air bubbles.

3. Check all oil lines and check all connections for damage. Look for oil on the ground under the machine.

4. Remove the hydraulic oil filter and examine the filter element for debris.

   1. Shiny steel particles indicate a pump failure or pump deterioration. Shiny steel particles can also indicate a motor failure or motor deterioration.

   2. Rubber particles indicate seal failures or hose failures.

   3. Bronze colored particles indicate pump port plate failure.

   4. Aluminum particles indicate a pump group failure or a vibratory motor failure.

      Note: When foreign particles are found, all hydraulic systems on the machine must be thoroughly flushed. Each hydraulic system must be filtered independently. Do not reuse damaged parts.

5. Inspect the control linkages for damaged components.

6. Check the machine for loose wiring. Check the machine for frayed wiring.

7. Inspect the steps and the handholds for damage or wear. Repair any damaged components or worn components. Inspect these areas for cleanliness. Clean the components.

Checks During Operation

Operation checks can be used in order to find a valve or a pump that is not working. The speed of rod movement or the torque on a motor can be used to check the condition of the cylinders, motors, and pumps.

1. Monitor the extension and monitor the retraction of the cylinders. The movement of the cylinders should be smooth.

2. Listen for irregular noise that may come from the pumps.

3. Listen to the relief valves. Low pressure in the relief valves may cause an increase in oil temperature. Also, cycle time of the cylinders may increase.

   Note: High pressure in the hydraulic system may decrease the service life of hydraulic system components.