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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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The drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the implement and steering pumps. Do not allow personnel into the pump bay area behind the cab when the engine is running. |
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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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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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
Note: Be sure to use the correct oil viscosity in the hydraulic system according to ambient temperature and operating conditions. To determine the correct oil viscosity, refer to the Lubrication Specification in Operation and Maintenance Manual, SEBU9122, "844K Wheel Dozer (T4F & LRC)"
- Move the machine to a location that is smooth, level, and hard. The location should also be dry and free of debris. Stop the engine.
- Permit only one operator on the machine. All other personnel should be kept away from the machine.
- Engage the parking brake. Lower the bucket to the ground. Put blocks in front of the wheels, and put blocks behind the wheels.
- Install the steering frame lock link.
- In order to relieve any brake oil pressure, push the brake pedal many times.
- Turn the key start switch to the ON position. Place the implement lockout switch in the DISENGAGED position. Cycle the hydraulic control levers through all positions 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 key start switch to the OFF position. Also, relieve all of the pressure in the hydraulic oil tank for the implement and the hydraulic fan system.
Note: The filler cap may be slowly loosened as another method of relieving the pressure in the hydraulic oil tank. Make sure that the filler cap is cool enough to touch with your bare hand.
- Relieve all of the pressure in the hydraulic oil tank for the steering and brake system. Locate the breaker relief valve. The breaker relief valve is mounted on the top of the hydraulic oil tank for the steering and brake system. Locate the plunger that is on the top of the breaker relief valve. Press and hold down the plunger.
- Make sure to remove all the oil pressure in both the steering and the brake systems before you adjust any fittings, hoses, or components.
Reference: For the correct procedure for releasing the system pressure, refer to Systems Operation/Testing And Adjusting, UENR4599, "844K Wheel Dozer (T4F & LRC) System Pressure Release".
- During the diagnosis of the hydraulic system, remember that correct oil flow and correct pressure are necessary for correct operation. The output of the pump increases as the engine speed increases. The output of the pump decreases as the engine speed decreases. Oil pressure is caused by resistance to the flow of oil.