Usage:
NOTE: The pilot relief valve is installed in the pilot manifold which is located behind the right rear access door of the engine/main hydraulic pump compartment.
Fluid Spillage Containment
Care must be taken to ensure that the fluids are contained during performance of the inspection, the maintenance, the testing, the adjusting and the repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to the "Tools And Shop Products Guide, NENG2500" the tools and the supplies suitable to collect and contain any of the fluids in Caterpillar machines. Dispose of the fluids according to local regulations and mandates.
1. Start the machine, and fully extend the stick and the bucket. Lower the stick and the bucket to the ground.
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At operating temperature, the hydraulic oil tank is hot and under pressure. Hot oil can cause burns. To prevent possible personal injury, release the pressure in all of the implement hydraulic circuits (the boom, the stick and the bucket) before any of the hydraulic lines or any of the components are disconnected or removed. |
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2. Release the pressure in all of the implement hydraulic circuits (the boom, the stick and the bucket) before any of the hydraulic lines or any of the components are disconnected or removed. Release the pressure as follows:
a. Shut off the engine and place key in the "ON" position. Put the hydraulic activation control lever in the "UNLOCK" position.
b. Move the control levers for the boom, the stick and the swing to all full stroke positions. This will release any pressure that might be present in the pilot system.
c. Return the key to "OFF" position.
d. Slowly loosen the fill plug on the hydraulic tank and release the pressure.
h. Tighten the fill plug on the hydraulic tank. Tighten the fill plug to a torque of 68 ± 7 N*m (50 ± 5 lb ft).
f. The pressure in the hydraulic system has been released and the hydraulic lines and the components can be removed.
3. Oil will drain out of the pilot manifold when the pilot relief valve is removed. Place a drain pan under the pilot manifold to contain the drain oil. Remove pilot relief valve (1) from the pilot manifold as follows:
a. Remove cartridge (8), spring (7), spool (3) and poppet (2) from the pilot manifold.
b. Remove O-ring seal (5) and plug (4) from the cartridge.
c. Remove the O-ring seal and back-up ring from the plug.
d. Remove nut (9) and screw (6) from the cartridge.
NOTE: The following steps are for the installation of the pilot relief valve.
4. Make sure all parts of the pilot relief valve are clean and free of dirt and debris. Put clean hydraulic oil on the components prior to the installation.
5. Install the pilot relief valve as follows:
a. Temporarily install nut (9) and screw (6) in the cartridge.
b. Check the condition of the back-up ring and the O-ring seal for plug (4). If the back-up ring and the O-ring seal are worn or damaged, use new parts for replacement.
c. Install the back-up ring and the O-ring seal on plug (4). Install plug (4) in the cartridge.
d. Install spool (3) in poppet (2). Install spring (7) and poppet (2) in the cartridge.
6. Install pilot relief valve (1) in the pilot manifold. Tighten cartridge (8) to a torque of 80 ± 8 N*m (60 ± 6 lb ft).
NOTE: Refer to the topic "Lubricant Viscosities and Refill Capacities" in the "Operation & Maintenance Manual" for the proper filling procedure and the proper levels for the hydraulic oil system.
7. Check the oil level in the hydraulic oil tank. Fill the hydraulic oil tank to the correct level.
8. Adjust the pilot relief valve pressure. Refer to the appropriate "320B, 320B L and 320B N Hydraulic Excavators, Hydraulic System Testing & Adjusting Manual", for the correct adjustment procedure.
9. After adjustment of the pilot relief valve pressure, tighten nut (9) to a torque of 16 ± 1 N*m (12 ± 1 lb ft).