CAP-SEALING 2430914 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below. Problem
The 297-0370 Check Valve Gp and 297-0371 Solenoid Valve Gp that is used in the auxiliary circuit and smart boom circuits may seize or stick. If there is any hard contamination that would flow through the valve, internal parts such as the spool might seize and cause a failure. The valve failures will result in a malfunction of the implements or tools.Solution
If a valve is seized, push the push rod with a tool like a driver. By pushing the rod, the seized internal parts are going to be released from the contamination and the valve will work. If the failure is not resolved after pushing the rod and the valve seems to cause the failure, return the valve to the quality assurance department. Send the valve to the attention of Kazuyuki Seo at the Akashi plant through the service engineers.Note: Never disassemble the valve.Procedure to Push the Rod
The release of hydraulic pressure in the hydraulic circuit is required before service is performed to the hydraulic circuit. Release the pressure in the hydraulic circuit before any hydraulic lines are disconnected or removed from the hydraulic circuit.Note: Refer to the Disassembly and Assembly Manual for additional information concerning service of the components of specific hydraulic circuits.
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 attachments 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.
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, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Perform the following steps in order to release the hydraulic pressure from the desired hydraulic circuit of the main hydraulic system:
Place the machine on flat level ground.
Fully retract the stick cylinder rod. Adjust the position of the bucket so that the bucket is parallel to the ground. Lower the boom until the bucket is flat on the ground.
Stop the engine.
Release the pressure in the stick and boom down hydraulic circuits. Refer to RENR6690 Testing & Adjusting Section, "Hydraulic System Pressure - Release Of Hydraulic Pressure From A Single Hydraulic Circuit".
Illustration 1 g02339436
Locate the push rod
Illustration 2 g02339442
Push the rod with a small round tool to release the seized parts.