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Dry nitrogen is the only gas approved for use in the accumulators. The charging of oxygen gas in an accumulator will cause an explosion. An explosion can be eliminated by using nitrogen gas cylinders with standard CGA (Compressed Gas Association, Inc.) No. 580 connectors. When nitrogen gas is ordered, make sure to order the cylinders with CGA No. 580 connectors. Do not rely on color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders. In any application, never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity). |
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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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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 work tools have been lowered to the ground, and the 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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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. |
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This procedure describes the method for testing and charging the ride control accumulator. The procedure includes the following:
- Shutdown procedure
- Nitrogen test and charging procedure
- Testing the ride control diverter valve
- Road test
- Start the engine and move the machine to a hard, level surface.
- Move the transmission control lever to the NEUTRAL position.
- Engage the parking brake.
Reference: For more information about preparing the machine for testing and charging the ride control accumulator, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting".
Show/hide table
Illustration 1 g06122910 Top view of right-hand control panel
(1) Ride control button - Place the ride control switch (1) in the Service position, that is the side indicated by a wrench icon. The ride control icon in the front display will turn yellow.
- Lower the bucket to the ground.
- Move the lift control lever to the FLOAT position. The hydraulic pressure in the accumulator will be relieved.
Reference: For more information about releasing the hydraulic pressure in the system, refer to the Service Manual module Testing and Adjusting, "System Pressure - Release".
- Turn the engine start switch key to the OFF position.
- Disconnect the hydraulic lines for servicing, as needed.
Nitrogen Test and Charging Procedure
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| Illustration 2 | g06122444 |
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View from right side of machine (2) Ride control accumulator (3) Nitrogen charging valve | |
Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures" for the required tooling, and the testing and charging procedure.
- Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures" for the required tooling, and the testing and charging procedure.
Note: The pressures in Table 1 are recommended for machines with typical buckets. For machines with heavy buckets, the nitrogen pressure may be increased. Increased pressure will keep the accumulator piston from striking an internal stop during normal roading while the ride control system is activated. However, raising the nitrogen pressure will result in a stiffer ride.
- Put a typical load in the bucket.
- Place the ride control switch (1) in the Service position, that is the side indicated by a wrench icon. The ride control icon in the front display will turn yellow.
- Drive the machine over a rough road surface.
If the accumulator piston is striking the stop, the nitrogen precharge pressure must be increased.
Note: The ride control accumulators are rated up to
35,000 kPa (5,100 psi) . Only add enough nitrogen in order to achieve a suitable ride for the typical payload of the machine.Reference: For more information on the Nitrogen Charging Procedure, refer to the Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures" for the required tooling, and the testing and charging procedure.
- Increase the nitrogen precharge pressure by
345 kPa (50 psi) and perform the road test again.