What’s Wrong With My Hydraulic Directional Flow Valve? A Troubleshooting Guide

If you work with complex hydraulics or monitor their performance, scheduling regular, careful valve maintenance checks is crucial. Why? Hydraulics rely on a variable one-way fluid loop to work – much like a one-way traffic system. Without fully working directional control valves, there’s nothing to ensure pressurised liquid keeps moving, returning, and pressuring as it should.

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Jammed, faulty, and underperforming units can cause unexpected downtime and endanger operators through micro-leaks and sudden system collapse. Malfunctioning valves can also cause damage to other parts of the system. Delicate pumps, control gates, mechanisms, and rotors are particularly vulnerable.

Due to the closed-circuit nature of hydraulics, it’s often too late to rectify valve failures if they occur when the system is in motion. Proactive flow valve monitoring helps identify the signs of directional flow valve failure before it occurs, preventing damage and allowing you to schedule maintenance at a time that suits your production needs.

What Is A Hydraulic Directional Control Valve?

A directional control valve is any one-way device that creates a single-direction flow of pressurised hydraulic fluid through a fixed loop. Directional control valves are placed on the in-line piping of hydraulics or next to vital components (i.e. pumps, cylinders, chambers). When unlocked, control valves pass moving hydraulic fluid through a small lock containing an unpowered actuating cylinder or interlocking spool array. Valves also help boost hydraulic pressurisation and performance by reducing backwash and resistance.

How Will I Know If My Directional Control Valves Are Malfunctioning?

Luckily, hydraulic directional flow valves often provide warning signs that they’re underperforming, broken, or wearing out, before giving way completely. With regular monitoring and visual inspections, you can also detect impending hydraulic valve failure from cross-referencing secondary signs of fatigue and unexpected fluctuations (i.e. overheating, sudden shifts in fluid flow, stalled engines and moving parts) with symptoms of mechanical stress.

If any critical signs start appearing, power-down the system immediately and book a maintenance check with a trained hydraulic engineer. Never attempt maintenance or repair on a hydraulic system while operating under load.

Look Out For:

  • Lowered Internal Pressure And Flow Rates – Dial indicators can show if a valve is performing outside of expected parameters.
  • Worn Bearings, Casings, O-Rings, And Connectors – All are key signs that a valve is coming to the end of its working life. Look out for flaking, frayed, holed, and pitted metal, plastic, and rubber.
  • Pools Of Hydraulic Fluid Close To Valves – Leaks are a sign that the valve is losing integrity or dropping fluid.
  • Strange Grinding And Scraping Noises – A common sign of internal part failure, particularly with spools.
  • Pilot Pressure Release Failure – Valves should open when the right level of fluid pressure is applied. If the valve is manually triggered and doesn’t activate, there may be issues with electrical wiring or secondary components.
  • Cylinder, Spool, Or O-Ring Misalignment – Faults during cylinder installation or O-ring replacement can cause directional flow valves to malfunction, even if there are no faults with the component itself.
  • Sudden Drops In Fluid Reservoir Levels – A sign of gradual, microscopic leaks caused by misaligned, or breached valves.
  • Slow Opening And Closing Motions – Valves should react near-instantly to triggers. Any slowdown can be due to part failure, misalignment, or internal build-ups of detritus.

Next Steps

At Hydrastar, our expert hydraulic design engineers can talk you through what you’ll need for safe diagnostics, replacements, and repairs, and system optimisation. Emergency repair services are available – as well as hundreds of brand-name, next-day-delivered hydraulic and pneumatic components. Please get in touch today to discuss your requirements.

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