Hydraulic Cylinder Troubleshooting: Common Issues and Fixes
Hydraulic cylinders do a lot of heavy lifting around Melbourne – whether it’s moving massive 40 foot containers around our port, huge cranes, to industrial plant and machinery like bar benders and proof loaders. When they start playing up, you’ll usually notice things like weak movement, drifting under load, or oil where it shouldn’t be.
We rely on these cylinders every day, so let’s walk through the usual suspects - leaks, drift, and loss of power - and some practical ways to tackle them.
Why Do Hydraulic Cylinders Fail?
There’s no single reason a cylinder stops behaving itself. Problems usually stem from either:
Something mechanically wrong inside the cylinder, or
A broader fault somewhere else in the hydraulic system – e.g. Grenading as we outlined in our previous article.
Common triggers include worn seals, damaged rods, internal bypassing, contaminated oil, or incorrect system pressures. Because a lot of these issues look similar from the outside, taking the time to diagnose properly is key. Flotek technicians spend the time to identify, and then fix the actual cause, not just the symptom.
External vs Internal Leaks
External leaks are the obvious ones. You’ll see oil around the rod area, on the gland, or pooling under the cylinder. This often points to:
Worn or damaged seals
Scored or pitted piston rods
Pressure spikes that push the cylinder beyond what it was designed to handle
Internal leaks are sneakier. They happen when oil slips past the piston seals inside the barrel. You don’t see oil on the floor, but you’ll notice the cylinder slowly moving under load on its own - a classic sign of “cylinder drift.”
First step for both: a good visual and mechanical check.
Inspect the rod for damage or corrosion
Check the seals and wipers
Confirm system pressure is within spec
If everything looks fine externally but performance is still off, you may need internal bypass testing to see whether oil is slipping past the piston inside the cylinder.
What’s Really Going On With Cylinder Drift?
Cylinder drift becomes a big deal anywhere the cylinder is meant to hold a load steady - think lifts, presses, stabilisers, or any setup where “stay put” really means “don’t move at all.” If the load slowly creeps down or shifts, something is letting oil move when it shouldn’t.
Common causes include:
Worn piston seals letting pressure leak across to the low‑pressure side
Internal leakage in valves (directional or check valves) that allows backflow and pressure loss
Air in the system, which can show up as jumpy or unpredictable motion, especially at startup or when things get hot
To pin it down properly, you generally:
Isolate the cylinder
Run pressure or flow tests
If the cylinder still drifts when it’s out of the circuit and plugged appropriately, you’re almost certainly looking at a cylinder problem. If it behaves when isolated, you’re more likely dealing with a valve or system issue somewhere upstream.
Loss of Power and Weak Cylinder Performance
Another common complaint is: “It used to push this load no problem - now it stalls or crawls.” Weak cylinders often show up as:
Stalling under load
Failing to complete the stroke
Moving slowly or inconsistently
Likely suspects:
Contaminated hydraulic fluid, which increases wear and drag, and slowly eats seals and surfaces
Air in the oil, making the system feel spongy or inconsistent
Bent rods or misaligned loads, which put side‑load on the cylinder and stop it from extending or retracting smoothly
In many cases, a professional rebuild is the sweet spot. If the barrel and main structure are sound (no cracks, no serious corrosion), rebuilding with new seals, rods, and properly finished surfaces can be quicker and more economical than chasing a new unit - especially for custom cylinders.
However, if the tube is badly worn, oval, rusted through, or the damage is widespread, replacement is usually the best long‑term choice. That’s also a good time to consider an upgrade - better materials, improved seals, or a design better matched to how the machine is actually being used.
Final Thought
At Flotek, we specialise in diagnosing and repairing hydraulic cylinder failures anywhere in Melbourne. Our expert technicians are trained in all aspects of cylinders, from in-depth inspection and testing, to complete cylinder rebuilds in our Melbourne workshop. You can even bring your cylinder into Flotek (Williamstown) for a full inspection.
