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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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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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- Move the machine to a smooth horizontal location. Move the machine away from other machines and personnel. Stop the engine. Engage the parking brake.
- Permit only one operator on the machine. Keep all other personnel away from the machine or in the operator's view.
- Put chocks in front of the tires and behind the tires.
- Install the steering frame lock to the LOCKED position.
- Unless a system test requires the front of the machine off the ground, do not stop the engine with the front of the machine off the ground. Lower the machine to the ground and stop the engine. Engage the parking brake.
- Move the attachment control levers to all positions in order to release the pressure in the hydraulic system. Place the tilt control lever in the HOLD position. Place the lift control lever in the HOLD position.
- Carefully loosen the filler cap on the hydraulic tank in order to release the pressure in the tank.
- Relieve all hydraulic pressure before loosening a fitting, a hose or a component. Relieve all hydraulic pressure before tightening a fitting, a hose or a component. Relieve all hydraulic pressure before removing a fitting, a hose or a component. Relieve all hydraulic pressure before adjusting a fitting, a hose or a component.
- Tighten the filler cap on the hydraulic tank.
- The pressure in the system has now been released and lines or components can be removed.
During the diagnosis of the hydrostatic system, remember that correct oil flow and correct pressure are necessary for correct operation. The output of the pumps decreases when engine speed decreases. Oil pressure is caused by resistance to the flow of oil.
When any test is made to the hydrostatic system, the hydraulic oil must be at normal temperature for operation. In order to increase the oil temperature, start the engine. Lift the bucket and tilt the bucket.
The 4C-4890 Hydraulic Test Group, 6V-7940 Hydraulic Test Group and 8T-5320 Hydraulic Test Group are used to make the pressure tests on the hydrostatic system. The pressure tests may also be done on the hydrostatic system with 1U-5481 Pressure Gauge Group. Before any tests are made, visually inspect the complete hydrostatic system and the attachments. Check the hydrostatic system and the attachments for leakage of oil. Check the hydrostatic system and the attachments for parts that have damage. For some of the tests, a magnet and a measuring rule (either inch or millimeters) are usable tools.