Buying a Used Tower Crane: The Complete Inspection Checklist

A well-maintained tower crane easily works for twenty-five years or more, which is why the used market is where most contractors buy. The economics are compelling — but only if the crane you buy is the crane you were promised. After decades of buying, inspecting, and selling used Potain cranes, this is the checklist we work through ourselves, and the one we recommend to every buyer, whether you buy from us or not.

Start with the paperwork, not the steel

More deals should die at the documentation stage than at the inspection stage. Before you travel to see a crane, ask for the document set. A serious seller can produce the crane's identification (type, serial number, year of manufacture — and verify these against the plates on the machine itself, not just the listing), the load charts and manuals for the specific configuration on offer, the inspection and certification history, and a maintenance log or at least service invoices. In the EU, the crane needs CE marking and, in practice, a paper trail that lets you get it certified in your own country — inspection regimes differ per member state, so ask explicitly what is included in the sale and what your national certification will additionally require.

Gaps in the paperwork are not automatically deal-breakers, but every gap is a negotiation point and a risk you are pricing in. A crane with no documented history should be priced like one.

Structure: where the real money hides

Structural problems are what separate a bargain from a liability, because structural repair costs routinely exceed what you saved buying cheap.

Work through the mast sections one by one. You are looking at the chords and lattice welds for cracks and repaired cracks (fresh paint over a small area of a weathered section is worth a question), at the pin and bolt holes for ovalization — elongated holes mean the section has been working loose — and at corrosion, distinguishing surface rust from pitting that has eaten into material thickness. Check that section types match and are genuinely compatible with this crane model; mixed lots happen in the used market.

On the slewing assembly, inspect the slew ring for play and ask when the bolts were last checked and torqued to specification. On the jib and counter-jib, walk the full length if the crane is erected: tie bars, pendant lines and their connection points, and the trolley rails for wear ridges. On the base or chassis, look at the condition of the anchoring points or the cross-base, and for a self-erector specifically, the folding hinges and hydraulic cylinders — the components that do the hardest work in that design.

Mechanisms and electrics: the operational heart

The hoist winch is the most valuable mechanism on the crane. Check the drum for rope-groove wear, the gearbox for leaks, and the brake — ask for a load test or at minimum a function test under power. The same logic applies to the slewing and trolley drives: listen to them run, watch for smooth acceleration, and note any drive that hunts or judders.

The electrical cabinet tells you how the crane has lived. A tidy cabinet with original wiring and legible schematics suggests professional maintenance; a nest of improvised repairs, bypassed contactors, or missing safety relays suggests the opposite. On more recent Potain models, control systems store fault histories and operating hours — ask for a readout. Verify that the safety devices are present and functional: load moment limiter, hoist limit switches, slewing limits where fitted, and the anemometer.

Wear items: cheap to replace, expensive to discover late

Some findings are normal and simply belong in the price. Hoist ropes have a defined discard standard — broken wires, kinks, corrosion, reduced diameter — and replacement is routine, but it is your cost if the rope is at the end of its life. The same goes for the hook and its safety latch, sheaves and rope guides, brake linings, and the trolley wheels. None of these should scare you off; all of them should show up in your calculation.

Hours, age, and the story they tell together

A twenty-year-old crane with modest hours that spent its life on long projects can be in better condition than a ten-year-old machine that was rented out weekly, transported constantly, and erected by whoever was available. Ask not just how old the crane is, but how it was used: owner-operated or rental fleet, long placements or short ones, coastal or inland (salt air ages steel and electrics alike). The transport and erection count matters more for self-erectors than anything else — folding cycles are their hardest duty.

Questions every serious seller answers without hesitation

Why is this crane for sale? What work did it last do, and where can I see it — erected, ideally under power? What is included: ballast, mast sections and how many, remote control, documentation? What did the last inspection find, and can I read the report? Has the crane ever had structural repairs, and by whom? Can my own inspector examine it before purchase?

That last one is the acid test. At NIBM we encourage independent inspections — a buyer's inspector confirming what we already know is the cheapest trust-building exercise in this industry. Any seller who resists third-party eyes on the crane is telling you something.

Dealer, auction, or private sale

All three routes can work, and we say that as a dealer. The honest difference is what happens when something is wrong. At auction you buy as-seen, often without power on the machine, and the discount reflects exactly that risk. Privately you depend entirely on your own inspection. A dealer stands between you and the risk: the crane has been inspected, the documentation is in order, delivery and often recommissioning are arranged, and there is someone to call afterwards. Which premium is worth paying depends on your own technical capacity — a contractor with an in-house crane technician can hunt auctions in a way a first-time buyer should not.

The bottom line

A used tower crane is one of the best capital purchases in construction when the machine's history, structure, and mechanisms all tell the same story — and one of the worst when they don't. Use the checklist, insist on documentation, bring your own inspector, and price every finding.

If you are earlier in the process and still deciding which model fits your projects, start with our guide on how to choose the right Potain tower crane. And if you want to see how inspected, documented cranes are presented, browse our current inventory of used Potain tower cranes — spec sheets and load charts for most models are freely available in our technical library, and for anything else, get in touch. We are happy to talk you through the inspection history of any crane in our yard.

Author: Gid Gehlen, NIBM Tower Cranes — decades of experience buying, inspecting, and selling used Potain tower cranes across Europe.