Factory Customized 2 Stage Hydraulic Cylinder — Small Dump Truck Multistage

Customized 2 Stage
Small Dump Truck
Valves That Protect the Cylinder & Control the Body

A telescopic hydraulic cylinder does not operate alone — it works within a hydraulic circuit that includes a pump, a directional valve, and critically, safety and control valves that protect the cylinder from damage and prevent dangerous uncontrolled movement of the dump body.

No load-holding valve on single-acting systems

The most dangerous misconfiguration. Some budget small dump truck conversions omit the load-holding valve to save cost — relying only on the directional valve spool to prevent body drift. Directional valve spools leak internally over time — the body slowly drifts down. This is a workplace safety issue. Always install a dedicated load-holding valve on single-acting telescopic cylinders.

PRV set to pump maximum instead of cylinder rating

Some installers set the PRV to the pump's maximum pressure rating rather than the cylinder's rated working pressure. If the pump is rated at 250 bar but the cylinder is rated at 200 bar, a 250-bar PRV setting exposes the cylinder to 25% over-pressure on every stall condition. Always set the PRV based on the cylinder's working pressure — not the pump's capability.

No lowering speed control on light bodies

Small dump trucks with aluminium bodies or empty steel bodies retract very quickly under gravity — the body drops with minimal resistance. Without a flow control restrictor on the return line, the lowering speed is uncontrolled and potentially dangerous. Install a needle valve or flow control on the return line to limit the lowering speed to a safe, controlled rate. This is especially important on 12V DC systems where the control valve may not include built-in flow regulation.

Does the cylinder come with valves included?

Standard orders include the cylinder only — valves are separate components selected and installed by the body builder or hydraulic system integrator. However, Korea Ever-Power can supply the cylinder with an integrated valve block (directional + relief + load-hold + flow control) as a complete hoist kit for OEM body builders who prefer a pre-configured system. Specify "hoist kit with valve block" in your inquiry if you want the integrated option.

My dump body drifts down slowly when parked — is the cylinder leaking?

Usually no — the cylinder is not the first suspect. Body drift is most commonly caused by a leaking load-holding valve (pilot-operated check valve) or internal leakage past the directional valve spool. Check the load-holding valve first — replace the O-rings or the entire valve if it is leaking past. If the load-holding valve is good, check the directional valve for internal spool leakage. Only if both valves are confirmed good should the cylinder's internal seals be suspected. The same diagnostic approach applies to all telescopic cylinders, forklift cylinders, and aerial platform cylinders.

How do I calculate the correct PRV setting for my cylinder?

PRV setting = cylinder rated working pressure × 1.10 to 1.15 (10–15% above working pressure). Example: cylinder rated at 180 bar → PRV set at 198–207 bar. Never exceed the cylinder's maximum rated pressure on the PRV setting. If your pump can produce 250 bar but your cylinder is rated at 180 bar, the PRV must be set below 207 bar — the pump capability is irrelevant to the PRV setting. The cylinder rating is the ceiling.

We build 3.5-tonne tippers with aluminium bodies and 12V DC power units. Previously omitted the load-holding valve to save £40 per truck — until one body drifted down overnight and damaged the tailgate mechanism. Now every truck gets a pilot-operated check valve. The Ever-Power 2-stage cylinder with the valve block option made installation much simpler — the directional valve, PRV, load-hold valve, and flow control are all in one manifold that bolts directly to the cylinder port. One hose to the pump, one hose to the reservoir — clean, safe, and fast to install.

Called in to diagnose a "leaking cylinder" on a small dump truck — the body was drifting down over 2 hours. Four stars for this page's FAQ section which helped me diagnose: the cylinder seals were fine — the load-holding valve had a worn O-ring allowing slow bypass. Replaced the O-ring ($3 part) and the drift stopped completely. Without the diagnostic guidance on this page, I would have pulled and resealed the cylinder unnecessarily — a 4-hour job instead of a 30-minute valve O-ring replacement. The lesson: check the valves before blaming the cylinder.