A crane rarely breaks down in a single day. Most major failures announce themselves months in advance: a slight loss of speed, an oil stain under a cylinder, an unfamiliar noise from the boom. When those signals are ignored, the result is a crane standing idle on site and a heavy repair bill. In this post we have listed the seven warning signs we see most often on the cranes that come into our workshop — the signs that tell you an overhaul is due.
An Overhaul Is Not the Same as a Repair
Let's separate the two terms first. A repair is a targeted fix for a fault that has already happened: the burst hose is replaced, the burnt-out coil is renewed, and the crane goes back to work. An overhaul is a planned process in which the machine's main systems are opened up, inspected and brought back to specification together, with worn parts renewed as a set:
- the hydraulic circuit and cylinders,
- the wire rope and sheave group,
- the slewing ring and turntable,
- the electrical system,
- the chassis and structural welds.
A repair saves today; an overhaul secures the crane's coming years. If several of the signs below appear at the same time, it is no longer a matter of one-off repairs — it is time to talk about an overhaul.
The 7 Signs That an Overhaul Is Due
1. Loss of Hydraulic Power and Slower Movements
A crane that struggles with loads it used to lift comfortably, extends its boom more slowly than before, or "hesitates" under load is losing efficiency in its hydraulic system. The cause is usually a worn pump, cylinder seals with internal leakage, or contaminated hydraulic oil. Power loss never fixes itself — and over time it pushes the operator into risky manoeuvres.
2. Oil Leaks
An oil film on a cylinder rod, sweating around hose fittings, a stain that grows a little every morning where the crane is parked... Every leak, however small it looks, steals system pressure and oil. A low oil level makes the pump draw air, and the resulting cavitation shortens its life. When a crane is leaking from several points at once, having the seals and hoses overhauled as a complete set is far more economical than replacing them one by one.
Practical tip: before the shift starts, look at the ground where the crane was parked overnight. The position and size of the stain is the most valuable information you can give the workshop about the source and severity of a leak — take a photo and keep it.
3. Wear on the Wire Rope and Sheaves
Broken wires, crushing, loosened strands or corrosion on the rope; deepened grooves and play in the sheave bearings — these are among the most critical signs of all. The rope and sheave group is the chain that carries the load directly, so wear here is not a performance issue but a life-safety issue. A crane with visible rope damage should not be put under load again until it has been overhauled.
4. Vibration and Jerky Boom Movements
Boom sections that snag as they extend, jerky, stop-start movement when lowering a load, or shuddering while slewing point to worn slide pads, pins and bushings that have developed play, or a valve block that is no longer working smoothly. Vibration is not just a comfort problem: it increases load swing and makes precision lifts risky.
5. Unusual Noises
A whistling or whining sound from the pump warns of cavitation, squealing from the slewing mechanism means gears running dry, and a metallic "click" under load points to play in the pins and bushings. An operator knows the sound of their own machine better than anyone. "It never used to make this noise" is one of the complaints we hear most often at our workshop — and one of the ones we take most seriously.
6. Delayed Controls and Electrical Faults
Functions that respond late to joystick commands, buttons that only work intermittently, blowing fuses and warning lights are signs of ageing wiring, oxidised connectors, or tired coils and relays. The treacherous thing about electrical faults is that they are erratic: on site they work one minute and fail the next. A delayed response in the middle of a critical lift is a risk nobody can accept.
7. Cracks in the Chassis and Weld Seams
Hairline cracks, blistered paint or rust traces around the boom connections, the outrigger (stabiliser) housings and the weld seams of the chassis mean the machine has been fatigued by heavy loading. A crack is damage that grows under load, and work must stop the moment one is spotted. If these points are patched with quick, improvised welding, the problem returns within weeks; they need to be properly cleaned, prepared and re-welded using the correct welding methods.
Act Early, Pay Less
These seven signs all have one thing in common: every one of them is cheap to fix early and expensive to fix late. There is no comparing the cost of a seal kit replaced on time with a burnt-out pump, or of a rope adjusted in the workshop with a rope that has snapped on site. And unplanned downtime never costs parts alone — a waiting construction site, lost jobs and idle operator days all end up on the same bill.
If you have noticed one or more of these signs on your crane, acting early always pays off. At our workshop in Milas we carry out fault diagnosis, periodic maintenance and complete overhauls for cranes of every brand, and we respond on site when needed. Take a look at our crane repair and maintenance service, our hydraulic spare parts and hydraulic hose pressing pages, and call us 24/7 with any question you have.