Evolution About Us TLM Objectives Services Offered Useful Information Did You Know Contact Us Feedback Customer's Appreciation Site Map Home     Glossary of Terms BIS standards Equivalent standard Metal Test Specimens Equivalent chart Hydraulic oils Trouble shooting Conversion Table Select Trouble Shooting Options Unusal Operating Noise Improper Operation of...... ..........> Pumps ..........> Valve ..........> Directional Control Valve ..........> Flow Control & Check Valve ..........> Cylinder ..........> Hydraulic Filter ..........> Hydraulic Motor ..........> Accumulator Hydraulic Fluid Problems Tubing and Pipe Grease Application Cutting/Griding Operations Improper Directional Control Valve Operation ........\\\///........ VALVE SPOOL WILL NOT RETURN TO CENTER   Possible Causes   Remedy 1) Pilot drain plugged. 1) See below:       a) Inspect internal or external drain ports for blockage. b) Inspect external drain line for kinks or collapsed line. Repair or replace as necessary. 2) Pilot valve stuck in one position. 2) See below:   a) Solenoid failure or seizure. b) Dirty or sticky spool. c) Improper spring tension.   a) Replace the solenoid. b) Remove and clean pilot valve spool. Drain, flush, and refill system with filtered recommended fluid. 3) Return spring(s) weak or broken. 3) Replace 4) Torque motor feedback spring broken (servo valve). 4) Replace 5) Contamination and/or burr on spool. 5) Remove, disassemble, and clean valve. Replace valve as necessary. Drain, flush, and refill system with filtered recommended fluid.   ........\\\///........ VALVE SPOOL DOES NOT SHIFT   Possible Causes   Remedy 1) Solenoid(s) failure. 1) Replace solenoid. 2) Low or no pilot pressure. 2) See below:   a) Source pressure low. b) Orifice(s) plugged. c) External pilot supply line damaged.   a) Check the pilot pressure source. Adjust as necessary to pilot pressure setting. b) Clean pilot orifices. Replace as necessary. c) Inspect pilot supply line. Replace as necessary. 3) Pilot valve or main valve spool sticking. 3) See below:   a) Dirty spool. b) Improper valve torque. c) Burrs on spool.   a) Remove and clean pilot valve spool. Drain, flush, and refill system with filtered recommended fluid. b) Torque valve to manufacturer's specifications. c) Disassemble and remove burrs, ore replace spool as necessary. 4) Torque motor failure. 4) Check for improper voltage. Ensure voltage is within manufacturer's specification. Perform electronics testing, replace failed cards as necessary. 5) Valve body distortion. 5) See below:   a) Improper valve installation. b) Excessive strain caused by external piping arrangement.   a) Loosen mounting bolts and retorque. b) Loosen rigid piping to remove strain. 6) Contamination. 6) Drain, flush, and refill system with filtered recommended fluid.   All rights of this site is reserved to Global Technical Services.       site design and maintained by Mod Graphics