Swing Bearing for Caterpillar 307B — Internal Gear

The Swing Bearing for Small Caterpillar Excavators is a precision-engineered rotary support component designed to replace the original slewing ring on CAT mini & small excavators below 20 tons. This single-row ball internal slewing bearing delivers steady 360° upper body rotation, bears moderate radial and axial loads, and maintains stable performance under light construction, landscaping and municipal working conditions. Manufactured by BRISK SLEWING, this small internal gear swing bearing fully complies with CAT OEM standards on outer/inner dimensions, raw material grade and integral heat treatment, enabling direct bolt-on installation without cutting or modification. It fits light daily operations such as house renovation, road greening and small trenching, greatly lowering your machine maintenance cost and downtime while keeping the same safety and durability as genuine CAT spare parts.

The small internal gear swing bearing for CAT mini excavators has standard technical parameters as below:

Outer Diameter: 780 mm; Inner Diameter: 560 mm; Overall Height: 68 mm;

Gear Type: Internal gear (standard); Number of Teeth: 86; Module: 8;

Material: Forged 50Mn steel, quenched and tempered;

Raceway Hardness: HRC 55–62; Gear Surface Hardness: HRC 50–60;

Sealing: Double lip NBR rubber seal, Viton high-temperature seal optional;

Lubrication: M8×1 grease nipple with smooth circulating grease groove;

Precision Class: Grade P5 (ISO 286);

Dynamic Load Rating (axial): 320 kN; Static Load Rating (axial): 860 kN.

All parameters are optimized for light load frequent swing of small excavators. Every finished bearing will pass full inspection of radial clearance, gear backlash and raceway hardness before delivery.

This small internal gear slewing ring is direct replacement for CAT mini & small excavators under 20 tons:

CAT 305.5, CAT 307, CAT 307B, CAT 307C, CAT 307D, E307C, E307D, CAT 215, CAT 311, E110, E215, E215B, 120B.

The mounting hole adopts M16 grade 10.9 high-strength bolts with tightening torque of 320 Nm. Our installation manual marks the soft annealing zone, which must be arranged on the zero-load idle area during assembly. Please measure your original bearing OD, ID and height before ordering to confirm matching.

4. Quality Standards & Certification

BRISK SLEWING operates under ISO 9001:2025 quality management system. Each swing bearing undergoes a multi-step quality control process: Raw material verification – chemical composition analysis and ultrasonic testing for internal defects; Forging and heat treatment – controlled quenching & tempering to achieve uniform hardness; Machining – CNC turning and grinding of raceways with surface roughness ≤ Ra 0.8; Gear cutting – hobbing or shaping followed by induction hardening of tooth flanks; Magnetic particle inspection – 100% inspection of raceways and gear teeth for cracks; Dimensional inspection – CMM measurement of all critical dimensions; Noise and rotation test – smoothness verification under load simulation. All test reports and material certificates are kept traceable and can be provided upon request. We also offer third-party inspection by SGS, BV, or TÜV at the buyer's expense.

CAT small excavator swing bearing supports all rotary operation of mini diggers:

Landscaping & municipal engineering – frequent low-load swing for tree planting, sidewalk repair;

Indoor demolition & small renovation – light impact load with breaker hammer;

Farmland trenching & irrigation – soft soil continuous rotation work;

Small material handling – loading sand, gravel and agricultural waste;

Rural road maintenance – narrow-space short-cycle excavation.

This small internal gear bearing series can also be matched with small aerial work platforms and mini industrial turntables. Intermittent rotation design matches the daily maintenance cycle of small construction machinery.

13+ Years of Experience – We have been manufacturing slewing rings since 2013, specializing in replacement parts for CAT, Komatsu, Hitachi, and other major brands. Our engineering team understands the unique failure modes of each model.

500+ Technical Drawings – We maintain a library of CAD drawings covering most popular excavator and crane models. You can request a free 2D drawing for verification before ordering.

Global Shipping & Logistics – We ship to over 60 countries via sea, air, or rail. Our logistics partners provide door-to-door delivery with customs clearance support. Average lead time to South America, Africa, and Southeast Asia is 15-25 days.

24-Hour Quick Response – Send us an inquiry with your machine model or OEM number. You will receive a quote within 24 hours, along with technical advice from our engineers.

OEM-Grade Quality at Lower Cost – Our bearings meet or exceed OEM specifications but cost 30-40% less. We offer a 12-month warranty against manufacturing defects.

Customization Available – Non-standard sizes, special seals (e.g. Viton for high temperature), and alternative gear configurations are available. We also accept OEM branding and neutral packaging.

Free Technical Support – We provide installation guides, bolt torque charts, and online remote assistance. For large orders, we can arrange on-site training.

📖 Technical Guide: Read our Installation Guide for Small CAT Excavator Swing Bearing → for bolt torque specifications, soft zone placement, and maintenance tips.

Frequently Asked Questions

1. What is the OEM part number for small CAT excavator swing bearing?

− Different mini CAT models correspond to independent OEM serial numbers. You can provide your machine model number, and we will match the corresponding replacement model SE-Series small slewing bearing, fully consistent with original size, material and heat treatment for direct assembly without modification.

2. Is this small internal gear slewing ring a direct replacement for CAT mini diggers?

− Yes, this BRISK SLEWING small swing bearing is fully developed as OEM replacement for CAT excavators ≤20 tons, including CAT 305.5, 307 series, E110, E215 etc. The mounting specification uses M16 grade 10.9 bolts with tightening torque 320 Nm. Measure your original bearing dimensions before placing orders.

3. What material and hardness grade are used for this small swing bearing?

− The slewing ring is manufactured from high-quality forged 50Mn steel, quenched and tempered to achieve a raceway hardness of HRC 55–62 and gear surface hardness of HRC 50–60. The precision class is Grade P5 (ISO 286), ensuring smooth rotation and long service life under light excavator loads.

4. What is the warranty period and do you provide technical drawings?

− BRISK SLEWING offers a 12-month warranty against manufacturing defects on all swing bearings. Yes, we maintain a library of 500+ CAD drawings covering most excavator and crane models. You can request a free 2D drawing for verification before ordering. Simply send us your machine model or OEM number, and our engineering team will provide the drawing within 24 hours.

5. How long does shipping take and which countries do you deliver to?

− We ship to over 60 countries worldwide via sea, air, or rail. Our logistics partners provide door-to-door delivery with customs clearance support. Average lead time to South America, Africa, and Southeast Asia is 15–25 days. For urgent orders, express air shipping is available. Contact our sales team for a precise delivery quote based on your location.