Why Your Hydraulic Cylinder Is Losing Power
Updated: 1 day ago
A hydraulic cylinder that drifts, slows down or can't hold a load is usually either losing oil past worn seals, or not getting full pressure and flow from the rest of the system. Check whether it's one cylinder or every function, look for leaks and rod damage, and get worn seals dealt with before they damage the rod or barrel.
Flow Force Hydraulics is a local family-run, Appin-based 24/7 mobile hydraulic repair service. Here's how to narrow down what's going on.
The usual signs
A boom, arm or blade that sags or creeps down under load
A bucket that curls out, or a tipper body that creeps down
One function that's slower or weaker than it used to be
Oil on the rod, or a ring of oily dirt around the gland
Jerky, spongy or uneven movement
First question: one cylinder, or everything?
If only one cylinder is weak or drifting, the problem is most likely that cylinder, its hoses, or its section of the control valve.
If every function is slow or weak, look at the system first: oil level, the pump, the relief valve, blocked filters, or oil that's overheating or contaminated.
Common causes
Worn piston seals (internal leakage)
Oil slips past the piston from one side to the other inside the cylinder. There's often no visible leak, but the cylinder drifts under load and loses force. Drift can also come from a leaking control valve or load-holding valve, so it needs to be diagnosed rather than assumed.
Worn rod or gland seals
Oil leaks out where the rod enters the cylinder. You'll see oil on the rod or a build-up of oily dirt at the gland. Left alone, it gets worse and lets dirt in.
A scored, pitted or bent rod
Scratches, rust pitting or a bend in the chrome rod chew through new seals quickly. A reseal won't last if the rod is damaged.
Dirt and contamination
Dirty oil wears seals and can score the barrel. A damaged wiper seal lets grit in every time the rod retracts.
Air in the system
Air makes movement spongy or jerky and can come from low oil or a leak on the suction side.
Low oil, pump wear or relief valve problems
These usually affect more than one function at once, and are worth checking before blaming a single cylinder.
A leaking hose or fitting
A weeping hose or fitting feeding the cylinder can also cost you pressure.
Simple checks you can do safely
Park on level ground and lower every attachment to the ground. Never work or stand under anything held up by hydraulics alone.
Check the hydraulic oil level.
Look for oil on the rod and around the gland, and check the rod for scores, pitting or a bend.
Check the hoses and fittings to that cylinder for wet spots or damage.
Note whether it's one function or several, and whether it's worse when the oil is hot.
Don't touch or feel for a leak with your hands. Oil under pressure can inject through the skin, and that needs urgent hospital treatment.
Reseal or rebuild?
Where the rod, barrel and mounts are in good condition, a reseal is usually all it needs. We remove the cylinder, take it away to be resealed, then bring it back and refit it.
If the rod is bent or badly scored, the barrel is scored, or there's internal damage, the cylinder needs more than seals. We arrange those rebuilds, including honing and machining, through trusted specialist workshops.
Either way, the repair is tested before the machine goes back to work.
What helps us when you call
The machine make and model, and where it is
Which cylinder it is, and what it's doing (drifting, slow, leaking)
Photos of the cylinder, the rod and any leak
Cylinder losing power? Call Flow Force Hydraulics 24/7 on 0459 698 249.
We're based in Appin and service the surrounding suburbs, from Wollongong to Penrith and Hornsby. Further afield on request. More on our hydraulic cylinder and ram repairs.
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