Spool off caused by the failure

Spool off, the control valve will show greater mechanical noise. Failure occurs, the control system can not be adjusted properly controlled variable sudden rise or fall. Failure analysis as follows.hydraulic banjo fittings
Control valve flow passage design is unreasonable, causing the spool to oscillate and subjected to shear forces, in the long-running process, the connection pin so that the spool and the valve stem breakage, so that the spool off. The Troubleshooting method is to check the control valve flow path, replace the pin.
2 valve plug pin is not securely installed, causing the spool off. The Troubleshooting method is reinstall the pin and tighten.metric hydraulic hose fittings