A Southworth LS-Series lift table that will not hold and one that will not lower are two different faults, not one tired cylinder. Before you open either hydraulic path, confirm the actual weight of the load is at or below the maximum allowed for that specific table. An overloaded unit behaves like a broken one, and every check after that is wasted motion.
Once the load is confirmed, the symptoms split cleanly. A table that creeps down while raised points at the down valve, its coil, the wiring and the cylinder vent line. A table that lifts fine but will not descend points at the down-valve solenoid and the flow control.
Check the Load Before the Hydraulics
Start on the floor, not at the valve block. The allowable load is a number for the exact table and configuration on your dock, read off its nameplate or its own manual, not carried over from another size in the same line. If the pallet, the fixture, or the load plus its attachments sits at or below that maximum, the hydraulics are your suspect and the rest of this applies. If it sits above it, reduce the load and retest before anyone touches a valve.
Time with a scale and a nameplate buys you the right to skip the whole valve and cylinder sequence, and skipping it in the wrong direction buys downtime. An overloaded table that gets corrected with an adjustment tends to come back on the next heavy pallet, and the technician who made the adjustment comes back with it.
Won't Hold? Start at the Down Valve
A raised table that settles on its own is a holding fault. Holding faults start at the down valve, and a short list of conditions is worth ruling out before anyone prices a cylinder.
The down valve may be leaking, so remove it and inspect for debris that may be keeping it from closing. The valve may also be energized, so make sure the coil is not energized when the up button is pushed, and verify there is no stray voltage to that coil preventing it from closing fully. The wiring deserves the same pass, because a conductor fault there can produce the same drift.
If you find debris, go with the down valve as the narrow repair path, working from the model manual rather than from habit. When the coil is live while the up button is pressed, the electrical command is the first thing to fix and the valve is innocent. If all three come back clean, do not order a cylinder on suspicion; move to the vent-line check instead. Meter and valve-inspection time is the price, and a cylinder swap that fixes nothing is the alternative.
None of that is a reason to put your hands into a raised table. Before any valve work, consult the model manual's procedure for securing the platform; the checks above only say what to look for.
Won't Lower? Check Voltage Before Flow
A table that goes up and refuses to come down is a lowering fault, and here I would spend the minute with a meter before touching the flow control. Check the solenoid in the down valve with a voltmeter first.
The reason is order, not taste. An energized down valve sits on the manufacturer's list of causes for a table that will not lower. A flow-control setting turned to compensate for a valve held closed looks like a fix right up until the next cycle. If the meter shows the coil energized when it should be releasing, go with the electrical path and leave the flow setting alone. A clean reading moves you to the flow control, adjusted as needed.
One extra measurement before an adjustment that takes almost no time is cheap cover against a flow setting that masks an electrical fault and sends you back to the same table later. Skip the meter only if the circuit has already been proven dead some other way.
Oil in the Vent Line Points to a Cylinder Leak
One check changes the direction of everything above, and it is oil in the cylinder vent line. That is the manufacturer's cylinder-leak indicator.
It takes a look and no parts, which is why it belongs inside the sequence rather than at the end of it. If oil is present in that vent line, stop swapping valve parts; the diagnosis has moved from valve and electrical to the cylinder itself, and further field adjustment will not hold. If the vent line is dry, stay on the valve and electrical path and keep the cylinder out of the conversation until something points there.
Either result pays for itself: a dry vent line costs you a look, and a wet one saves a parts bill that was never going to stop the drift.
After a Cylinder Leak, Service or Replace
The published material stops short of a replacement interval, a repair price, or a field cylinder procedure, so the last call is a judgment rather than a rule. Here is how I would frame it for a procurement decision.
If the load is within the rated maximum, the down valve and its wiring are clean, the flow control has been checked, and oil is present in the cylinder vent line, the checks have converged on a cylinder leak. That table goes to qualified hydraulic service, or into a repair-versus-replace comparison built from the model manual, current parts availability, and a written service quote. If those earlier checks are not clean, do not replace the table yet, because you have not finished diagnosing it.
What the ordered checks buy is a narrow repair instead of blind parts swapping: one valve, one coil circuit, or one service call, chosen on evidence rather than on which part is easiest to order. What they cost is the shortcut. Load verification, a meter reading and a vent-line look all come before anything is fixed, and if the vent line is wet, the cheap field fix is off the table and downtime goes toward a proper repair or a replacement decision.
