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Hydraulic oil pressure can remain in the hydraulic system on this machine after the engine and pump have been stopped. Serious injury can result if this pressure is not released before any service is done on the hydraulic system. In order to prevent possible injury, release the hydraulic system pressure before working on any fitting, hose, or hydraulic component. Lower all work tools to the ground before service is started. If the hydraulic system must be serviced, tested, or adjusted with the work tool in the raised position, the work tool and lift cylinders must be supported properly. 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. |
| NOTICE |
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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 machine. 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 Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids. Dispose of all fluids according to local regulations and mandates. |
| Cylinder Drift | ||
| Date | Equipment ID Code | |
| Description | Specification | Actual |
| Cylinder Drift Per Minute | |
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Reference: Before you perform this test, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting".
Hydraulic cylinder drift is any movement of the cylinder rod, when the cylinder rod is in the HOLD position. During normal operation, movement of the cylinder can affect the performance of the machine.
Any of the following examples may cause cylinder drift:
- The cylinder piston seal is damaged.
- A scratch in the cylinder bore or a groove in the cylinder bore
- A scratch on the cylinder rod or a groove on the cylinder rod
- The cylinder head seal is damaged.
- Dirt in the lock valve or the lock valve is damaged in the implement control valve.
- Loose fittings or damaged hydraulic lines that have oil leaks.
- Dirt in the line relief valves, or the line relief valves are damaged.
Tools are not required for this test procedure.
- Move the machine to a smooth horizontal location.
- Chock the wheels.
- Lower all the implements.
- To test for cylinder drift, the oil temperature should be
38° to 50°C (100° to 122°F) . Extend the cylinder rod halfway and put the cylinder rod in the HOLD position.Note: The pressure should never exceed
42000 kPa (6090 psi) . - The piston shall not move more than
3 mm (0.12 inch) per minute. - Inspect all welds and seals for leaks. Note any unusual noise from testing to determine damaged seals.