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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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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system. |
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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 in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. |
- Park the machine on a smooth, level surface. Move away from other operating machines and away from personnel. Lower the bucket and/or attachments to the ground. Stop the engine.
- Permit only one operator on the machine. Keep other personnel away from the machine or in the operator's sight.
- Engage the parking brake. Place blocks in front of the wheels and behind the wheels.
- When the bucket and/or attachment is raised for testing or for adjusting, make sure that the bucket and/or attachment is supported correctly. Also, make sure that the bucket and/or attachment is fully in the DUMP position.
Note: Do not stop the machine with the front of the machine off the ground unless this is required for a test. Lower the machine to the ground and stop the engine. The lift circuit has high oil pressure when the lift arms raise the front of the machine.
- Place the steering frame lock link in the locked position so that the machine can not articulate.
- Turn the engine start switch to the ON position. Place the implement lockout switch in the ON position.
- Cycle the hydraulic control levers through all positions in order to release the pressure in the hydraulic system. Place the lift control lever in the FLOAT position. Place the tilt control lever in the HOLD position.
- Turn the engine start switch to the OFF position.
- To relieve all of the pressure in the hydraulic oil tank, push in the plunger on the breaker relief valve until all hydraulic pressure is released.
Note: The hydraulic tank filler cap may be removed instead, but using the plunger on the breaker relief valve is a safer method of relieving the tank pressure.
During a diagnosis of the hydraulic system, remember that correct oil flow and correct pressure are necessary for correct machine operation. The pump output increases as the engine speed increases. Furthermore, the pump output decreases as engine speed decreases. Oil pressure is caused by resistance to the flow of oil.