Demag Overhead Crane Parts: 7 Checks Before You Accept a Delivery

Last month I rejected a delivery of Demag overhead crane parts. Not because anything looked wrong at first glance—the boxes looked right, the labels looked right, and the photos the supplier sent before shipping showed exactly what we ordered. The paperwork was the problem. The certificate of conformity listed a batch number that did not match the number stamped into the brake drum hub. Could have been an honest admin mistake. For a part that keeps a hoist from dropping a load, I don't accept “probably fine.”

I work as a quality and compliance manager for a crane service company. Since 2021 I have reviewed somewhere around 300 deliveries of Demag spares a year—hoists, brakes, controllers, motors, wire ropes, you name it. In 2025 we rejected about 8% of first deliveries. Most were small things that could be fixed by a return and replacement. A few would have shut down a customer's plant if we hadn't caught them.

If you buy Demag crane parts for your own fleet, for customer repairs, or as a distributor sourcing OEM components for mobile cranes and overhead cranes, this is the buying guide I wish I had when I started. Seven steps, roughly in order. Step 3 is the one people roll their eyes at—until it saves them.

The 7-step checklist

1. Start with the physical part, not your records

Most wrong-part orders I see start with a part number from a maintenance spreadsheet, not from the crane itself. Cranes get modified over their lives. Motors get swapped, drives get upgraded, brake systems get revised. The part number that worked “last time” might have been superseded twice since then.

Before you call a supplier, take two photos: one of the hoist nameplate and one of the stamping on the old part. Note the crane model and serial number. Then check what the parts documentation says for that specific serial number. It sounds obvious, but skipping this step is how people end up with the wrong part on a 10-ton crane and a very unhappy production manager.

In 2022 I ordered fifteen hoist limit switches from memory. They were for the previous generation of that Demag hoist. I still have the bin under my bench.

2. Get fitment confirmation in writing, for your serial number

A serious supplier asks for the crane model, hoist type, and serial number before quoting. If a distributor quotes you a universal brake kit without asking a single question about what it's going on, treat that as a red flag.

Our purchase orders now include the crane type, the hoist serial number, the part number stamped on the old component, and a note that says: supplier to confirm fitment in writing. If the part turns out to be wrong and the supplier disputes it later, you want that confirmation on record. This matters even more for older machines, because Demag parts get superseded over time and the number in an old manual may not be the number you should order.

3. Ask about storage conditions before you pay

Look, I get it: asking about how a supplier stores parts sounds like paranoia. Then you get a “new old stock” component that has been sitting in a humid warehouse since 2016 and wonder why the seals are hard or the motor bearings feel rough.

New and factory-fresh are not the same thing. This is a real issue in the crane spare parts market, especially on bulk hoist wholesale orders where parts can sit in inventory for years.

Ask the supplier three questions:

• How long has this item been in stock?
• Is it stored indoors, off the floor, in a dry area?
• Can you send a close-up photo of the date codes on rubber seals or bearings?

Seals and o-rings age. Bearings can corrode. Control boards can absorb moisture. A good wholesaler won't be offended by those questions. A supplier who is trying to move a decade-old shelf warmer might be.

4. Match the paperwork to the actual parts before signing anything

This is where the delivery I mentioned at the top failed. The certificate of conformity listed the right part number and quantity. But the batch number on the certificate didn't match the batch number on the brake drum. That small mismatch turned a straightforward order into a two-week delay.

For every safety-related component, match four numbers:

• delivery note part number
• certificate part number
• part number stamped on the component
• batch or serial number on the certificate vs. the batch or serial number on the part itself

If a component's batch number doesn't match its own certificate, don't accept a “we will re-issue the certificate” offer. A corrected certificate does not make the part more traceable. It just makes the paperwork look better, and that's exactly the wrong reason to change it.

5. Measure the critical dimensions before you install anything

Paperwork can be fully in order and the part can still be outside spec. It's rare with genuine components. When it happens, it tends to be expensive.

A few years ago we received a batch of hoist brake pads that looked exactly right—OEM part number on the box, right shape, right material color. They were about 2 mm thicker than the drawing. Installed, they would have dragged on the brake drum, caused overheating, and reduced braking torque when the crane was under load. A two-minute check with a caliper caught it. The supplier replaced the batch, but only after a long conversation about who pays for the downtime.

You don't need to measure every dimension. Check the ones that matter: friction material thickness, shaft or bore diameter, hole spacing, keyway width. Spin bearings by hand. If anything feels rough or binds, stop.

6. Dry-fit, then test under no load before the crane goes back to work

If the part is going onto a crane that runs over people's heads, don't let schedule pressure skip the functional check. We do a dry fit first: mount the part, confirm nothing binds, and make sure the moving parts actually move.

Then, with the hoist empty, run the hook through its full travel, check both limit switches, and run several brake stop/release cycles. Only after that do we load-test and hand the crane back. We also record the new part number in the maintenance file. If your inspection regime follows ISO 9927-1 or similar, that record matters when the inspector shows up.

7. Price the whole risk, not just the part

I'm a quality person, so you might expect me to ignore price. I don't. But I price the risk, and that looks different from what most people compare.

Not long ago I went back and forth between two suppliers for a Demag wire rope hoist component. Supplier A was an established authorized distributor, about 15% higher. Supplier B was a trader with a lower quote and a very confident tone. Supplier B might have delivered the exact same part. But “might have” is not a basis for a component that keeps a load suspended.

Best case, we saved maybe a few hundred dollars on one order. Worst case, the part was not what it claimed to be, we lost two or three weeks of project time, and a customer had to explain to their management why their crane was down. The math never justified the risk. We ordered from Supplier A.

This applies even more if you're buying for resale. A distributor can save 15% on a hoist wholesale order and nobody remembers. Deliver one untraceable brake component to a plant, and that relationship changes fast.

Mistakes that still cost people money

A few patterns show up again and again, even from buyers who know the Demag product line:

• Asking “is it genuine or not?” and stopping there. Genuine is the starting point, not the final answer.
• Checking the paperwork after the part has already been installed.
• Skipping the no-load test to save an hour—and losing three days when something fails.
• Comparing unit prices while ignoring freight, downtime, testing time, and return handling.

If you're setting up a wholesale hoist order or qualifying a new distributor, my advice is simple: order one sample first, run the full checklist on it, and only then release the rest of the batch. That small delay has saved us more than once.

I didn't write this list because I'm a perfectionist. I wrote it because one bad order taught me what a wrong crane part actually costs. These checks take about twenty extra minutes per order. For a part that could fail over someone's head, that's a fair trade.