Walt — Simple Man Takeaway
A cylinder that will not move may be obeying the load, not disobeying the valve.
Walt says STOP! - Safety First
Make these checks prior to proceeding.
Hydraulic systems can contain injection hazards, trapped pressure, suspended loads, stored energy, and sudden motion. Stop and follow qualified hydraulic and lockout procedures before loosening fittings, reaching into motion paths, or working under supported loads.
Guided Flow
Check each step as you work. This is a first-check flow, not a replacement for lockout/tagout, OEM procedures, qualified authority, or site rules.
1. Control pressure and load hazards
Protect people from stored energy and suspended motion.
- Identify gravity loads, trapped pressure, pinch/crush zones, and accumulators.
- Never check leaks with hands.
- Support loads mechanically when required.
2. Confirm command and permissives
Verify whether the system is being told to move.
- PLC output, solenoid light, manual valve position, enable/permissive, safety circuit.
- Is another station blocking motion?
3. Confirm pressure and flow availability
Separate supply issue from actuator issue.
- Pump running?
- Pressure available?
- Relief open?
- Filter clogged?
- Fluid level and temperature correct?
4. Check valve shift and direction
Confirm the valve actually shifts.
- Solenoid energizes?
- Spool stuck?
- Manual override response?
- Flow control closed?
- Counterbalance/lock valve holding?
5. Check mechanical bind and load path
Do not blame hydraulics for a jammed machine.
- Cylinder rod bent?
- Pins seized?
- Guides binding?
- Load too high?
- Frame or bracket shifted?
6. Check cylinder condition
Separate internal leakage from external restriction.
- Seal bypass clues.
- Rod damage.
- Uneven speed.
- Cylinder drifts under load.
- Oil heating from bypass.
7. Make one controlled adjustment
Change only after evidence supports it.
- Mark original settings.
- Do not crank relief or flow controls blindly.
- Test safely under controlled conditions.
8. Record cause and prevention
Capture the lesson.
- Command problem, pressure problem, valve problem, mechanical bind, cylinder problem, or load-path problem?
Discovery Questions
Related Pages and Tools
Boundary
This flow is practical field guidance. It is not OEM procedure, safety approval, engineering sign-off, lockout/tagout instruction, or permission to bypass guards, interlocks, or qualified authority. Humans remain the authoritative part of the machine.