When speed matters, a stalled hydraulic cylinder is costing you money. Every hour it sits out of service is downtime you are paying for. When your cylinder is pulled from service, it comes to our workshop. From there it runs the same sequence every time: strip, measure, machine, reseal and pressure test. This is what happens at each stage. Each step decides whether your unit goes back to work or needs replacing. The process is the same whether you send us a small actuator or a large-bore hydraulic ram. It holds whether the fault is a weeping gland or a rod that no longer holds load.
If you are not yet sure what is wrong with your unit, start with our guide to hydraulic cylinder repairs. It walks through the six conditions we see most often on the bench. An overhaul is one of the hydraulic repairs we carry out in Perth and across Western Australia. This page follows the unit through that overhaul.
Your cylinder comes apart cold, never with heat
The first thing we do is dismantle the unit on the bench, and because we run 24/7, an urgent teardown does not wait for the next business day. We strip cylinders across a 2–18 inch bore range without applying heat. Our in-house Nutcracker takes apart the large-bore units at the top of that range. Heat distorts glands and barrels during strip-down and puts a fault into a unit that did not arrive with one, so the rod, piston, gland and seals come apart cold. Working cold keeps the barrel and gland true, because every measurement taken next is compared against the original geometry.
Every part gets measured before we decide anything
Nothing is repaired until it is measured. The rod is checked for straightness and diameter along its full length. The bore is measured at several points along the stroke, and at right angles at each point. That is the only way to tell general wear from ovality, and the two lead to different work. These measurements decide whether your cylinder is repaired or replaced, so they happen before any machining, not after.
Bringing the barrel back to a true bore
Where the barrel has worn, it is honed to bring the bore back within its pressure rating. Oversize piston seals are then fitted to suit. Where ovality has gone too far to hone out within that rating, the barrel is replaced and the rest of the cylinder is reused. On custom units, and on cylinders with non-standard mounts or ports, reusing the sound parts is usually the better call. A full replacement has to be manufactured from scratch.
Saving the rod, or knowing when to replace it
A rod with light scoring is polished. A rod with deeper damage is ground undersize, re-chromed, then ground back to its original diameter. The new chrome surface then runs true against fresh seals. A new rod is manufactured instead where pitting has reached the base metal. The same applies where the rod is already at the limit of its remaining wall. A re-chromed rod that is also bent puts the same seal failure straight back into service. That is why the straightness measurement comes first.
Hydraulic repairs in Perth: reassembly with a full set of new seals
The unit goes back together with all soft parts replaced, not just the one that failed. Wear bands and bearings are checked and renewed where needed. We keep major components and common seal kits in stock on-site, so a standard rebuild is not left waiting on parts. A reseal is the most common repair we carry out, but new seals on their own do not fix a cylinder, they fix a symptom. That is why the rod and bore are put right first, so the fresh seals run on surfaces that will not destroy them.
Nothing leaves until it holds pressure
Before your cylinder is returned, it is pressure tested as a complete assembly, so the unit is proven to hold load before it goes back on your machine rather than after. On marine and defence work, documented inspection is carried out where the application calls for it. If your unit needs certification, tell us at enquiry, because it changes how the job is planned and scheduled.
The overhaul at a glance
- Strip-down: dismantled cold on the in-house Nutcracker, no heat. Why it matters: heat distorts glands and barrels, so working cold protects the original geometry.
- Measurement: rod checked for straightness and diameter, bore checked for wear and ovality. Why it matters: the measurements decide repair or replacement before any machining.
- Honing: barrel honed true and fitted with oversize seals, or replaced. Why it matters: restores the bore within its pressure rating without scrapping the whole unit.
- Re-chroming: rod polished, or ground and re-chromed, or replaced. Why it matters: gives the seals a true surface to run on.
- Reassembly: all soft parts, wear bands and bearings renewed. Why it matters: new seals last only as long as the surfaces around them.
- Pressure testing: complete unit tested, documented where required. Why it matters: your cylinder is proven to hold load before it ships.
The questions that hit our bench most often
How long does a hydraulic cylinder overhaul take?
Lead time depends on what the strip-down finds and on parts. A unit that needs only new soft parts moves quickly. One that also needs the barrel honed, the rod re-chromed, or a new rod or seal kit manufactured takes longer, because that is machining and supply time rather than assembly time. Send the unit’s details and we will tell you what yours needs before you commit.
Can you overhaul a cylinder if the data plate is missing?
Yes. Most cylinders can be identified from their bore, stroke, rod diameter and mount configuration, so send photographs of the full rod, both mounts and the unit itself even if the plate is gone.
Do you overhaul large-bore cylinders?
Yes. We overhaul cylinders across a 2–18 inch bore range, and our in-house Nutcracker strips the largest units cold, so big glands and barrels are not distorted during strip-down.
What is the difference between a repair and an overhaul?
A repair puts right a specific fault, such as a reseal to stop a weeping gland. An overhaul strips the whole unit, measures every component, and restores the rod, bore and seals together so the cylinder goes back to its original specification. If a unit keeps coming back, an overhaul that fixes the underlying cause is usually the more economical route.
Ready to get your cylinder off the bench and back to work?
Our workshop sits inside the Australian Marine Complex at Henderson. We are a Western Australian-owned business, established in 1992. We overhaul cylinders for marine, mining, defence and transport operators. Is your unit somewhere in Perth or regional Western Australia, and no longer holding load? Send its make, model, bore, stroke and rod diameter, with photographs of the damage. We will tell you whether it is worth overhauling before any work starts.
Contact Fremantle Hydraulics with your cylinder details.