CAT 168-8391 82.075mm Inner Diameter Roller Bearing Race

CAT 168-8391 is a track roller seat for Caterpillar tracked construction machinery. It is compatible with the track roller assemblies of Cat 320D, 323D and other excavators. It is used to position and support the track rollers, distribute the load and protect the internal bearings, ensuring smooth operation of the track system and extending the life of the roller assembly (Cat® Parts). The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 168-8391, Type: Track Roller Seat Ring (Single Flange), Material: Ductile Iron (QT500-7), Surface Hardening Treatment (HRC45-50), Single Weight: Approx. 4.2 kg, Working Temperature: -30℃ to +120℃, Rated Load Capacity: 350 kN, Impact Strength ≥20 J/cm², Fatigue Life ≥8000 hours

Key Dimensions
Inner Diameter: 120.0 mm (Tolerance 0/+0.025 mm), Outer Diameter: 180.0 mm (Tolerance 0/-0.025 mm), Width: 50.0 mm (Tolerance ±0.15 mm), Flange Thickness: 12.0 mm, Mounting Hole Diameter: 16.0 mm (3 evenly distributed, Tolerance +0.010/+0.020 mm), Inner Hole Surface Roughness Ra≤1.6 μm, compatible with roller shaft diameter 120.0 mm (tolerance – 0.010/0 mm)

Compatible Models and Applications: Compatible with Cat 320D, 323D, 326D and other tracked excavators. Used for outer positioning of the track roller assembly. Matching part numbers: 168-8392 track roller, 168-8393 seal. Prevents axial movement of the roller and protects internal bearings from mud, water and dust intrusion.

Performance Parameters: Wear resistance meets ISO 3547 standard. With construction machinery-specific grease (Cat Moly-Dee grease recommended), no significant wear after 1500 hours of continuous operation; corrosion resistance meets ISO 9227 standard, no rust after 72 hours; axial clearance ≤0.10 mm, radial runout ≤0.05 mm after assembly.

Structural and Performance Advantages: Ductile iron material + Surface hardening ensures both high strength and wear resistance, making it suitable for high-frequency impact and heavy-load conditions in track systems, reducing the risk of breakage and deformation.

A single-flange positioning structure precisely limits the axial displacement of the track rollers, preventing friction between the rollers and the track frame and ensuring smooth track movement.

The sealing groove design accommodates dedicated sealing rings, achieving an IP65 protection rating, effectively preventing the intrusion of mud, water, and dust in harsh construction environments, extending the service life of internal bearings.

Standardized mounting holes require no additional machining, allowing for quick assembly with the track frame, reducing maintenance and replacement time and costs.

Installation and Maintenance Points: Before installation, clean the seat ring mounting surface and track roller shaft, checking for burrs and cracks; tighten the seat ring onto the track frame using bolts (matching M16×80 high-strength bolts), with a bolt torque of 120-130 N·m, ensuring the coaxiality of the seat ring and roller is ≤0.08 mm.

After installation, check that the track bearing and rollers fit well, without looseness or abnormal noise, and that there is no uneven wear on the track during operation. Regularly check the condition of the seals; replace them immediately if aging or damage is observed.

Maintenance: Check the wear of the track bearing every 1000 hours. If the flange thickness wear is greater than 1.5 mm or if peeling or cracks appear on the surface, replace it immediately. When replacing, prioritize original parts to ensure compatibility with the track rollers and seals.