Return to Master Table of Contents TROUBLESHOOTING - JOYSTICK CONTROL VALVE Page 29 Hydraulic System Troubleshooting, Testing and Adjustment Problem Possible Causes Remedies Secondary pressure does not increase Low primary pressure Check primary pressure Broken spring Replace spring Spool sticking Clean, repair or replace Excess spool to casing clearance Replace spool casing Worn or loose handle subassembly Repair or replace handle subassembly Secondary pressure too high Dirt, other interference between valve parts Clean, repair or replace Return line pressure too high Redirect return line Secondary pressure does not hold steady Dirt, other interference between valve parts, or worn spool sticking intermittently Clean, repair or replace Interference or binding on spool return spring Clean, repair or replace Unsteady pressure in tank return line Redirect return line Air bubbles in piping (temporary) or air leak Vent air, or repair leak NOTE:
Look for evidence of leaking oil to help locate damaged seals or gaskets that could be the cause of air leaks.