Machine Preparation
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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, 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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Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine. To prevent personal injury or death, perform the following: Park the machine on a smooth, level surface. Lower the work tool to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock. |
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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause 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. Always use a board or cardboard when checking for a leak. |
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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, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
- Park the machine on a smooth, level surface. Park the machine away from working machines and personnel. Lower the work tool to the ground.
- Allow only one operator on the machine. Keep all personnel away from the machine or in the view of the operator.
- Engage the parking brake.
- Place the steering frame lock into the LOCKED position.
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| Illustration 1 | g00926858 |
- Warm the hydraulic oil to a temperature between 54 °C (130 °F) and 82 °C (180 °F).
Note: When you increase the temperature of the hydraulic oil, do not hold the control lever for more than ten seconds.
- Turn the engine start switch to the OFF position and remove the key.
- Move the control levers several times through the full range of travelwith the key in the ON position. This should relieve the pressure in the hydraulic system.
- Place the bucket on the ground or a stand in order to relieve pressure from the ride control system.
- Remove the appropriate guards.
- Ensure that any hose assembly or any component is clean before removal from the machine or the component is disassembled.
Procedure
When you are defining a problem in any of the hydraulic systems, the following procedure should be followed:.
When possible, talk to the operator of the machine. Ask about the symptoms of the problem: machine performance, noises, smells and frequency of the problem. Perform a visual inspection of the machine. Look at the following items:
- Check the display of the monitoring system for the following machine conditions: alert indicators, warnings and service codes.
- Be aware of the work environment. An extreme work environment can greatly affect the symptoms of a machine.
- Check the hydraulic oil level in the sight gauge.
- Look for air in the hydraulic tank oil immediately after the engine is stopped. Use a clear container to obtain a sample of the oil. Look for air bubbles in the oil in the container.
- Remove the hydraulic oil filter and cut the filter open with a filter cutter. Look for particles in the filter elements. A magnet will separate the ferrous particles such as iron and steel from the nonferrous particles such as brass, aluminum, and rubber.
- Check all oil lines and all connections for damage and for leaks.
- Inspect all of the hydraulic cylinders for damage and for leaks.
- Inspect all of the control linkages for components that are bent, broken, or damaged.
If the visual inspection does not identify the problem, perform the mechanical system tests. If the mechanical system tests do not identify the problem, perform the electrical system tests.
For additional help in resolving a problem, refer to Troubleshooting Manual, RENR8999, "Machine Systems". The troubleshooting manual lists the probable causes of a known problem.
Since more than one cause may exist for a problem, the troubleshooting section may suggest specific inspections or instrument tests. These inspections and tests will help identify the most probable cause.
Test Equipment
The following test equipment may be used in order to perform the hydraulic testing procedures.
- 1U-5481 Pressure Gauge Group
- 1U-5482 Pressure Adapter Group
- 198-4240 Digital Pressure Indicator
- 9U-7400 Multitach
- 1U-6602 Photo-Tachometer
- 304-9375 Thermometer
- 237-5130 Digital Multimeter or 257-9140 Digital Multimeter
- 213-4310 Thermometer
Troubleshooting Procedure
Use the following six steps in order to begin troubleshooting the machine:
- Know the machine.
- Understand the symptom.
- Verify the symptom.
- Determine the probable causes.
- Reduce the list of probable causes.
- Test the system.
Use the previous steps in order to troubleshoot this machine.
Know the Machine
Understand the operation of the machine. Know if the symptom is characteristic of normal operation or if the symptom is an indication of component failure.
Read the systems operation information in order to understand the systems of the machine. You must understand the interaction of the systems on the machine.
Understand the Symptom
Question the operator about the problem.
- Ask about the performance of the machine prior to the symptom.
- Determine the time of the first occurrence of the symptoms.
- Determine the operating conditions at the time of the symptom.
- Ask the operator about the sequence of events prior to the symptom. Determine the order of the occurrences.
- Ask the operator about the steps that have been taken to troubleshoot the machine.
- Ask the history of repairs of the machine.
- Ask about the preventive maintenance of the machine. Many failures are due to poor maintenance.
Inspect the machine. Look for problems. Notice any unusual odors in the air. Listen for unusual noises.
Verify the Symptom
Operate the machine. When possible, repeat the conditions which caused the symptom. Check the gauges inside the cab. Notice any unusual odors in the air. Listen for unusual noises.
Determine the Probable Causes
Once information is gathered create a list of probable causes. Determine the subsystem that is the cause of the symptom. Use the list of probable causes in Troubleshooting, RENR8999, "Machine Systems" as a guide.
Reduce the List of Probable Causes
List the probable causes in order of probability. Identify the probable causes that are easy to verify. When possible, eliminate probable causes that are easy to check.
Test the System
Use operational tests to verify the cause of the symptom. Once the cause has been identified, repair the suspect component. Then, test the system again. After completion of the testing and adjusting procedures, place the steering frame lock into the STORE position.