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6.2 Directional Solenoid Valve Troubleshooting
SYMPTOM POSSIBLE CAUSE CORRECTIVE ACTION
Valve does not shift but full line No or low hydraulic pressure. Check.
voltage signal is present at the
terminal strip inside the control.
Faulty field wiring. Check for full line voltage at the
solenoid.
Solenoid coil burnt out. Replace coil if no continuity through
coil.
Valve clogged or stuck.
Remove & clean. Or replace.
6.3 Hydraulic Components Troubleshooting
6.3.1 Cylinder Leaking
A. External Leakage
1. Rod seal leakage can generally be traced to worn or damaged seals. Examine the piston rod for wear or
damage. Replace the rod and seals if rod's surface is rough or worn out-of-round.
B. Internal Leakage
1. The lip seal piston seals are virtually leak free unless they are worn or damaged. Replace defective
seals.
2. Contaminants in the hydraulic supply can lead to scored cylinder walls, resulting in rapid seal wear. If
such is the case, check to see if the filter is being replaced frequently. A different type of filter may be
required; one that can remove finer particles or one that can filter out different kinds of contaminants.
3. Possible piston cylinder leakage, apparently indicated by piston drift is not always traceable to the piston.
A leak through a closed valve port can also cause piston drift.
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