EWP hydraulic systems are designed to be robust, but they do develop faults — and the symptoms are often more obvious than owners expect once you know what to look for. The difficulty is that some hydraulic problems develop gradually, making it easy to normalise a machine that is already performing below standard. This guide covers the main warning signs that point to a hydraulic fault, how serious each is, and what your next step should be.
Visible oil leaks
An oil leak is the clearest hydraulic warning sign and should never be ignored. Common leak points include: cylinder rod seals (weeping or dripping from the rod end of a cylinder), hose fittings and couplings (a slow seep that coats surrounding components with oil and dust), the hydraulic tank breather or return filter cap, and control valve bodies.
Even a small leak degrades hydraulic fluid levels over time, which leads to performance loss and can damage the hydraulic pump if the system runs low. Any visible oil leak should be investigated promptly — do not top the reservoir and continue operating.
Slow or uneven boom and platform movement
Hydraulic cylinders are what moves the booms and platform, so a cylinder that is developing internal seal wear or bypass will show up as sluggish or hesitant movement. If one function (say, the main boom lift) is noticeably slower than it used to be — or if movement jerks or hesitates rather than being smooth — a cylinder or control valve fault is a likely cause.
A machine that operates normally in cooler conditions but slows significantly once warm is also a common sign of internal hydraulic wear: bypassing seals allow more oil to slip past internally as the fluid thins under heat.
Drift — a platform or boom that creeps downward
If the platform or a boom section drops slowly when held stationary — often called 'creep' or 'drift' — this is a hydraulic fault. In a properly functioning system, hydraulic load-holding valves prevent any movement when the controls are not operated. Drift means a valve or cylinder seal is allowing oil to bypass, and the rate of drift tends to worsen as the fault progresses.
Drift is a safety concern as well as a mechanical one — a machine that will not hold its position is not compliant for use.
Machine stops or cuts out mid-operation
Many EWPs have over-pressure protection built in: if the hydraulic system reaches a pressure beyond what is safe, the machine cuts movement and may trigger a warning or fault code. This can happen because of a genuine overload — trying to operate beyond the platform's rated capacity — but it can also point to a pressure relief valve that is set or performing incorrectly, or to a failing pump.
A machine that trips on low loads, or that trips and resets repeatedly, needs a hydraulic pressure assessment before further use.
Unusual noise from the hydraulic pump
The hydraulic pump should run at a consistent, relatively quiet pitch. Whining, cavitation noise (a raspy or rattling sound that changes with load), or knocking from the pump are signs the unit is either starved of oil, has air in the system, or is beginning to wear internally. Catching a pump fault early is considerably cheaper than replacing one that has failed completely.
What to do next
If you observe any of these symptoms, the machine should be taken out of service until it is assessed by a qualified hydraulic technician. Operating with a known hydraulic fault — particularly drift or a pressure fault — creates a risk to operators and anyone working near the machine.
A technician will carry out a pressure and function test to identify the fault, explain the scope of what needs to be repaired, and provide a documented assessment before any work proceeds.
This guide is general information prepared by EWP Australia and is grounded in publicly available Australian Standards and Safe Work Australia material. It is not a substitute for the current published edition of the relevant standard or for site-specific engineering advice. Always work from the current standard and consult a competent person for your specific equipment and application.