CAT 385 390 Gear Slewing Bearing Swing Ring
The CAT 385 / 390 slewing bearing is a precision-engineered swing ring designed to provide stable rotation, load control, and long-term durability for Caterpillar’s large-frame excavators.
| Material | 50Mn/42CrMo |
|---|---|
| Surface Hardness | HRC58-62 |
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Kinton Parts is trusted by professionals worldwide for delivering high-quality parts for excavators, bulldozers, and other construction machinery—with guaranteed performance and durability.
On machines as large and powerful as the CAT 385 and CAT 390, the slewing bearing is the structural heart of the excavator. It connects the upper frame to the undercarriage, carries the full working load of the boom and bucket, and ensures controlled, accurate rotation during every digging and loading cycle.
This slewing bearing is designed specifically for Caterpillar’s large-class machines, where both mechanical precision and extreme strength are equally critical.
Designed for Heavy Axial and Overturning Loads
During deep digging, rock breaking, or truck loading, CAT 385 and 390 excavators generate enormous axial and tilting forces. The slewing bearing is engineered with a raceway profile that spreads these forces across a wide contact area, reducing localized stress and improving fatigue resistance.
This design helps maintain structural stability of the upper frame even when the machine is working at full reach or lifting heavy material off-center.
High-Stiffness Ring Structure
The bearing rings are produced from high-strength alloy steel and undergo controlled heat treatment to achieve an ideal balance between surface hardness and internal toughness. The hardened raceways resist wear from rolling elements, while the tough core absorbs impact loads and vibration generated by aggressive digging.
The result is a bearing that remains dimensionally stable and resistant to deformation over long service intervals.
Precision-Machined Raceways for Smooth Rotation
Accurate machining of the raceways ensures consistent rolling contact and even load distribution. This allows the upper structure of the CAT 385 / 390 to swing smoothly, without binding or uneven resistance, even when carrying a fully loaded bucket.
Smooth rotation also reduces stress on the swing motor and reduction gearbox, contributing to longer service life of the entire swing system.
Optimized Gear Engagement
For models with an integrated ring gear, tooth geometry is designed to match Caterpillar’s swing drive characteristics. This provides steady torque transfer, reduced noise, and improved positioning control during both slow slewing and rapid rotation.
Stable gear engagement is especially important during repetitive truck-loading cycles, where precision and consistency directly affect productivity.
Forged Ring Pre-Machining
Our process begins with high-quality alloy steel rings (typically 42CrMo), forged and polished for flatness and crack-free integrity. These rings form the structural base of both inner and outer components.
Gear Cutting on Inner Ring
The inner ring undergoes CNC gear milling to create a tooth profile that precisely matches Volvo swing pinions. After cutting, teeth are quenched and tempered to resist wear and deformation during high-load engagement.
Final Packing & Storage
After inspection, the slewing bearings are coated with anti-rust oil, wrapped in plastic, and packed in strong wooden crates. Labels include model code, part number, and batch information for easy identification and shipping control.
Model Fitment – CAT Swing Bearing Applications
We have slewing bearings that can match the following models.
| BRAND | MACHINERY MODEL NUMBER | |||||||
|---|---|---|---|---|---|---|---|---|
| CATERPILLAR-CAT | CAT55 | CAT225 | CAT245 | CAT311 | CAT312 | CAT312B | CAT315 | CAT320 |
| CAT320B | CAT320C | CAT320D | CAT320L | CAT322 | CAT324 | CAT325 | CAT325B | |
| CAT325BL | CAT330 | CAT330B | CAT330BL | CAT330C | CAT330D | CAT345 | CAT345B | |
| CAT973 | E55 | E70 | E70B | E120 | E120-1 | E120B | E140 | |
| E200B | E200-5 | E215 | E240 | E300B | E300L | E311 | E312 | |
| E312B | E320 | E320BL | E320C | E320D | E320DL | E320L | E320S | |
| E322B | E322C | E324 | E324D | E324DL | E325 | E325B | E325L | |
| E329DL | E330 | E330B | E330C | E330D | E330DL | E345 | E345B | |
| E450 | CAT301.5 | CAT302.5 | CAT303.5 | CAT305 | CAT307 | CAT308 | CAT313 | |
| CAT316 | CAT318 | CAT320E | CAT320GC | CAT323 | CAT326 | CAT329 | CAT336 | |
| CAT340 | CAT349 | CAT350 | CAT365 | CAT374 | CAT375 | CAT385 | CAT385CL | |
| CAT390 | CAT390D | CAT390DL | CAT390FL | CAT395 | CAT6015 | CAT6015B | CAT6015D | |
| CAT6020 | CAT6020B | CAT6030 | CAT6030B | CAT6030D | CAT6040 | CAT6040B | ||
Still not sure about your part number? Send us the machine serial number, casting code, or technical sketch, and we’ll verify compatibility within 12 hours.
Sealing System for Harsh Job Sites
Mining and heavy earthmoving environments expose the slewing bearing to dust, mud, water, and abrasive debris. The sealing system used in this bearing is designed to keep lubricant inside while preventing contaminants from entering the raceways.
This protection significantly reduces internal wear and helps preserve the smooth rolling performance that large excavators depend on.
Accurate Fit and Long-Term Reliability
The mounting surfaces and bolt hole geometry are carefully controlled to ensure correct alignment on both the upper frame and undercarriage of CAT 385 and CAT 390 machines. Proper fitment ensures uniform preload, stable load distribution, and reliable long-term operation.
A correctly installed slewing bearing not only improves swing performance but also protects surrounding structural components from unnecessary stress.
Supporting Stable and Productive Operation
A high-quality slewing bearing allows the CAT 385 and 390 to operate with predictable, controlled movement. This stability improves operator confidence, reduces shock loads to the boom and frame, and helps maintain precise positioning when working in tight or high-value job sites.
Over time, this translates into less downtime, lower maintenance cost, and higher machine availability.
SHIPPING & DELIVERY
At Kinton Parts, we ensure reliable, worldwide shipping of parts for excavators, bulldozers, and a full range of construction machines—safe, fast, and secure.
All products are securely packed using high-quality export cartons, reinforced wooden cases, or industry-standard palletized packaging to ensure maximum protection during transit and smooth handling during unloading.
Standard orders are typically shipped within 3–5 working days, while large or customized orders are usually dispatched within 7–20 days, depending on volume and production requirements.
We offer flexible global shipping options, including:
- International sea freight for cost-effective bulk transport
- Air freight for urgent orders
- Courier delivery (DHL, FedEx, UPS) for small-volume or sample shipments
Our logistics team manages every shipment carefully, providing real-time updates and tracking information until your order arrives safely at your destination.
Need assistance choosing the best shipping method for your location and timeline? Contact our team — we’ll help you plan a smooth delivery experience.
FAQ
Q: What are your main products?
A: We supply a full range of undercarriage and wear parts for excavators, bulldozers, and other heavy equipment. Our product line includes: Track rollers, carrier rollers, front idlers, sprockets, segments, track shoes, track chains, bolt and nuts, pins and bushings, bucket teeth and adaptors, filters, seal kits, swing bearing, and hydraulic cylinder—plus other essential replacement parts.
Q: Which countries do you export to?
A: Kinton Parts exports to over 60 countries worldwide, including:
USA, Canada, UK, Germany, Russia, UAE, Indonesia, Malaysia, Thailand, India, Pakistan, Bangladesh, Sri Lanka, South Africa, Colombia, Peru, and many others.
Q: Can I order a sample?
A: Yes, we accept trial orders. For parts in stock, samples can be shipped quickly. If you have technical drawings or existing samples, we also support customized production and mold development.
Q: How can I track my order after shipping?
A: Once your order is shipped, we will provide you with all necessary tracking information based on the shipping method. For express deliveries, you’ll receive a tracking number to follow the shipment online. For air or sea freight, we’ll send you the relevant documents such as the airway bill (AWB) or bill of lading (B/L), along with the packing list and commercial invoice to help with tracking and customs clearance.
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Trusted by professionals worldwide, Kinton Parts supplies premium-quality components for excavators, bulldozers, and more—with reliable quality you can count on.
