In my career in the sealing industry, I have worked with cranes of many types—tower cranes on construction sites, gantry cranes at ports, overhead cranes in steel plants. While the designs vary, one fact never changes: once the sealing system fails, the whole machine is at risk of downtime. Many distributors and maintenance engineers often ask me: what types of seals are used in cranes, and what makes them different? Let me share some practical insights.
The Common Seal Types You’ll Find in Cranes
· O-rings
This is the simplest and most universal sealing part. It may look like a small rubber ring, but without it, many connections would leak immediately. You’ll see O-rings in gearbox covers, valve bodies, and slewing bearings. Most are made from NBR (nitrile), FKM (fluoroelastomer),. I recall a port crane where the valves were leaking because standard NBR rings degraded quickly in salty air. Switching to FKM solved the issue.
· Rotary shaft seals (oil seals)
These are used in gearboxes, motors, and slew drives. Their job is to hold the lubricant in and keep dust or water out. For ordinary environments, NBR is fine; for hotter or abrasive conditions, FKM or PTFE are better options. In one steel plant project, gearbox shaft seals hardened due to heat. We later switched to high-temperature material and extended service life significantly.
Every lifting and telescoping movement of a crane relies on hydraulic cylinders. Inside, you’ll find piston seals, rod seals, guide rings, and wipers. These seals must tolerate high pressure and constant motion. I once encountered a tower crane where the rod had fine scratches; seals kept failing in a few weeks. After changing to polyurethane rod seals combined with a stronger guide ring, the service interval nearly doubled.
· Gaskets and seal rings
In flange connections and hydraulic lines, composite gaskets (metal + elastomer) are used to resist both pressure and leakage.
· Wiper seals
Often underestimated. Positioned at the rod end of hydraulic cylinders, they
keep dirt, sand, and moisture out. Once contaminants enter, even the best
internal seals cannot last long.
Why Material Choice Matters
Distributors sometimes ask me: “Can’t we just use one material for everything?” I wish it were that simple. Environments differ a lot:
· A port crane faces salty air, so corrosion resistance is critical.
· A steel plant crane must cope with heat and dust, so high-temperature and wear-resistant seals are needed.
· A construction site tower crane mainly requires cost-effective, standardized parts.
That’s why choosing the right seal always means balancing structure and material with the actual working condition.
After years of working with wholesalers and resellers, I can tell you their main concerns are very practical:
· Is there always stock for the common sizes?
· If a customer needs a non-standard seal, can the factory design and deliver it quickly?
· When end users complain about leakage, can the supplier give a technical solution, not just send parts?
This is where the DEDE brand has built a reputation:
· Stock supply: more than ten thousand O-ring and oil seal sizes are available, with fast shipment for urgent demands.
· Customized service: engineers support material selection, design, and testing for non-standard requirements, ensuring the seals actually fit the environment.
· Technical empowerment: with over 30 years in sealing, DEDE not only sells seals but also helps optimize the system, reducing downtime and maintenance costs.
For a distributor, these points often weigh more than unit price. As one reseller told me: “My reputation is on the line when my customer’s crane is stuck. I need a supplier that responds fast, not just cheap.”
In this industry, many companies talk about innovation, but fewer have the track record to show it. DEDE strengths are solid:
· A full-scale manufacturing factory with complete models in stock;
· Sales to over 80 countries, with recognition from global brands;
· Certified as a Provincial Innovation Center, a Specialized & Innovative Enterprise, and a High-Tech Company;
· Leader within the regional industrial cluster, closely linked with upstream and downstream partners.
For distributors, this translates into supply reliability, stronger brand recognition, and better support when issues arise in the field.
So, to answer the original question—what types of seals are used in cranes? The list includes O-rings, oil seals, hydraulic cylinder seals, gaskets, and wipers. Each type has its role, and the choice of material is tied closely to the crane’s working environment. For distributors and wholesalers, the critical factor is not only price but whether the supplier can provide immediate stock, handle custom requests, and support problem-solving when failures occur.
With its broad product line, engineering expertise, and worldwide supply
network, DEDE has positioned itself as a partner that helps keep cranes running
safely and reliably, while giving distributors the confidence that they can
serve their own customers without interruption.
