This is the procedure for testing the pressure in the all wheel drive accumulator. An incorrect charge in the all wheel drive accumulator will result in pressure spikes in the case drain lines from the all wheel drive piston motors.Detail...
There are two all wheel drive accumulators. There is one all wheel drive accumulator for each all wheel drive piston motor. There is one all wheel drive accumulator on each side of the front axle. The all wheel drive accumulators are provided in order to reduce the pressure spikes in the all wheel drive piston motors. These pressure spikes occur when the all wheel drive system is operating at low ambient temperatures. The all wheel drive accumulators also provide a reservoir for the oil that is pushed out of the all wheel drive piston motors. The all wheel drive accumulators prevent excessive pressure from causing damage to the Duo-Cone seals. The Duo-Cone seals are located on the shaft of the all wheel drive piston motors.System Operation
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".
Test Step 1. Perform the following test: Machine Preparation for Troubleshooting
Results:
- OK - Proceed to test step 2.
Test Step 2.
- Check the nitrogen charge in the all wheel drive accumulators. Refer to the charging pressure and temperature relationship table for the proper nitrogen pressure at the ambient air temperature.
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive) - Test".Specifications
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".Systems Operation
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".Photo
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| Illustration 1 | g00544076 |
ACCUMULATOR GAUGE GRAPHIC | |
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| Illustration 2 | g00544077 |
ACCUMULATOR LOCATION GRAPHIC | |
Expected Result:
The pressure in the all wheel drive accumulators will be high, low or OK.
Results:
- The pressure is LOW. - Proceed to test step 3.
- The pressure is HIGH. - Proceed to test step 4.
- The pressure is OK. - Stop.
Test Step 3.
- Charge the all wheel drive accumulator to the correct pressure.
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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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Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".How...
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive) - Test".Photo
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| Illustration 3 | g00544076 |
ACCUMULATOR GAUGE GRAPHIC | |
Expected Result:
The pressure in the all wheel drive accumulator is correct.
Results:
- No - Proceed to test step 5.
- Yes - Stop.
Test Step 4.
- Remove the excess nitrogen charge from the all wheel drive accumulator.
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When the valve is opened with pressure in the cylinder, direct the flow of nitrogen away from all personnel. Pressurized nitrogen can cause serious injury. This procedure should be performed in an area that is well ventilated. High pressure gas can cause suffocation due to oxygen deficiency. |
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| Illustration 4 | g00544076 |
ACCUMULATOR GAUGE GRAPHIC | |
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive) - Test".Specifications
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".
Expected Result:
The pressure in the all wheel drive accumulator is correct.
Results:
- Repair Complete - Stop.
Test Step 5.
- Replace the all wheel drive accumulator. Use a new Caterpillar part for replacement.
Reference: Refer to Troubleshooting, "All Wheel Drive Accumulators".Parts
Reference: Refer to Troubleshooting, "8X-2518 LINES GP-MOTOR-AWD PIN 1AL1-UP. PART OF 8W-6310 DRIVE AR-ALL WHEEL".Specifications
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".
Expected Result:
The all wheel drive accumulator has been correctly installed.
Results:
- Continue - Proceed to test step 6.
Test Step 6.
- Charge the all wheel drive accumulator to the correct pressure.
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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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Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive) - Charge".Specifications
Reference: Refer to Troubleshooting, "Accumulator (All Wheel Drive)".Photo
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| Illustration 5 | g00544076 |
ACCUMULATOR GAUGE GRAPHIC | |
Expected Result:
The pressure in the all wheel drive accumulator is correct.
Results:
- Repair Complete - Stop.