PISTON RING GROUP 9H1224 - Caterpillar

Introduction
The following procedure can be used in order to test the pilot oil accumulator. The pilot oil accumulator maintains pressure in the pilot hydraulic system.When you test the pilot oil accumulator, the pressure in the pilot hydraulic system must be released. The temperature of the nitrogen gas must also be taken into account. The pressure and volume of nitrogen gas varies with temperature.Required Tools
Table 2
Required Tools
Part Number Description Qty
1U-5481 Pressure Gauge Group(1) 1
1U-5482 Pressure Adapter Group 1
4C-6486(2) Stand 2
8S-7641(2) Tube 2
8S-8048(2) Saddle 2
8S-7615(2) Pin 2
6V-3965 Fitting 1
214-7568 O-Ring Seal 1
(1) The 198-4240 Digital Pressure Indicator is also available.
(2) Optional toolingTest Preparation
Reference: For more information about preparing the machine for troubleshooting, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
Move the machine to a smooth horizontal location. Move away from working machines and personnel. Lower the work tools to the ground.
Allow only one operator on the machine. Keep all personnel away from the machine or in the view of the operator.
Engage the parking brake.
Illustration 1 g02703117
Place the steering frame lock in the LOCKED position.
Illustration 2 g00384713
Position the lift arms on the stands. Turn the engine start switch to the OFF position.
Illustration 3 g02703156
Remove the front guard group in order to access the main control valve.
Illustration 4 g02717521
Remove the plug at the front right corner of the main control valve. Refer to Illustration 4.
Illustration 5 g02717566
Install 6V-3965 Fitting and 214-7568 O-Ring Seal into the open port.
Connect 1U-5481 Pressure Gauge Group or 198-4240 Digital Pressure Indicator Gp to the pressure tap. Test Procedure
Start the engine and run the engine at HIGH idle. The pressure gauge will read 3450 150 kPa (500 20 psi).
Stop the engine. Turn the start switch to the ON position. Do not start the engine.
Watch the pressure gauge. Move the control lever or the joystick in order to lower the boom. The pressure will steadily decrease.
When the pressure is approximately 1000 50 kPa (145 7 psi), the pressure will suddenly drop to zero. The drop occurs because no oil is left in the accumulator. The final pressure prior to the sudden drop to zero is the approximate pressure of the accumulator charge.
Refer to Table 1. If the accumulator charge is incorrect, replace the accumulator.
After completing the test, remove the test equipment. Reinstall the plug in the main control valve.