Hydraulic Cylinders Out of Sync? Diagnose Uneven Travel
Two cylinders on one supply do not automatically move together. Equal pressure does not ensure equal flow, and equal flow does not ensure equal speed when effective areas differ.
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Start with the synchronization method
A tee connection gives the fluid competing paths; it is not a synchronizer. A divider/combiner has an operating range and finite accuracy. Series cylinders depend on the specified volume relationship. Feedback systems also depend on sensor calibration and control behavior.
Record the error pattern
- One side leads immediately: compare loading, friction, effective cylinder areas and plumbing.
- Error grows through the stroke: investigate flow division, leakage and unequal areas.
- Positions match after an approved reset but diverge again: inspect the rephasing system and accumulated flow error.
- Mismatch occurs only on return: compare annulus areas, return-flow control and counterbalance behavior.
Compare safe measurements
With the machine secured and tested under its approved procedure, record commanded movement, left and right positions, oil temperature and branch pressures. A qualified technician can verify branch flow and cylinder or valve leakage using rated test equipment. Do not disconnect a live hose to compare flow.
Check the divider’s operating envelope
Compare the installed valve’s part number, flow range, specified accuracy and synchronizing capability with the actual duty. Divider models differ; a generic 50:50 description is not a precision guarantee. Contamination, operation outside the rated range and restrictions can affect the result.
Rephase only when the system supports it
Some circuits provide controlled synchronizing flow at the end of stroke. Others do not. Use the machine maker’s reset procedure and time limits; do not hold an unknown circuit against relief to force alignment. Stop if the structure racks or the load becomes unstable.
Before replacing seals
Check mechanical guides, mounts, load distribution, cylinder dimensions and valve function. Confirm a leakage path before resealing. For a Case Board question, include a circuit sketch, synchronization method, travel error and whether the fault changes with direction, load or temperature.
To connect this inspection with the next repair decision, see Cylinder Bypass or Control Valve Leak? How to Separate the Two Causes of Drift.
Technical references
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