CAT 386-4210 68mm Diameter Self Aligning Bearing

The CAT 386-4210 is a genuine Caterpillar self-aligning roller bearing, suitable for heavy-duty swaying parts such as the swing mechanism and boom pin joint of Cat 320D2/323D2 excavators. It is used to compensate for installation coaxiality errors and absorb impact loads. The following is pure raw data and does not include replacement parts information.

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes
Model 386-4210, Type: Self-aligning roller bearing (double row symmetrical spherical rollers, inner ring with tapered bore 1:12, outer ring with retaining groove), Material: Inner ring/outer ring/rollers are high carbon chromium bearing steel (GCr15SiMn, quenching hardness HRC 60-64), Cage is stamped steel plate (SPCC, galvanized surface), Single weight 7.2 kg, Applicable shaft diameter φ80 mm, Rated radial load ≥280 kN, Rated axial load ≥100 kN, Operating temperature -40℃ to +120℃, Allowable self-aligning angle ≤2.5°, Lubrication method: Grease lubrication (recommended lithium-based grease, dropping point ≥180℃), Protection class: IP65, Assembly interference fit 0.015-0.030 mm

Key Dimensions
Inner diameter φ80 mm (tapered bore 1:12, tolerance + 0.02/+0.01 mm), outer diameter φ140 mm (tolerance 0/-0.02 mm), width 38 mm (tolerance ±0.15 mm), roller diameter φ16 mm (tolerance ±0.02 mm), roller length 25 mm (tolerance ±0.10 mm), cage pocket diameter φ16.05 mm, stop groove width 8 mm (tolerance ±0.10 mm), stop groove depth 3 mm (tolerance ±0.05 mm), roundness ≤0.01 mm, cylindricity ≤0.015 mm

Performance Parameters: Dynamic rated load Cr=285 kN, static rated load C0r=320 kN, fatigue life ≥12000 hours (rated load cycles), coefficient of friction ≤0.002 (grease lubrication, speed ≤500 rpm), limiting speed grease lubrication 1800 rpm, oil lubrication 2400 rpm, impact toughness ≥20 J/cm² (-20℃), roller surface roughness Ra≤0.05 μm
Structural and Performance Advantages
Double-row self-aligning design: Spherical rollers automatically align themselves, compensating for installation coaxiality errors and shaft deflection, suitable for heavy-load oscillating conditions.

Tapered inner ring: 1:12 tapered bore with adapter sleeve for easy axial positioning and preload adjustment, improving assembly accuracy.

Stabilizing groove outer ring: Can be fitted with a retaining ring to prevent axial movement of the bearing, suitable for conditions with high vibration and impact.

High carbon chromium bearing steel material: Quenching treatment ensures high hardness and wear resistance; stamped cage balances strength and lightweight.

Installation and Maintenance Points (Original Data)

Installation: Clean the journal and bearing housing bore (free from oil, rust, and impurities). Install using a locknut (fitted to φ80 mm shaft diameter). Preload torque 120-150 N·m. After installation, check bearing clearance (radial clearance 0.04-0.06 mm). The gap between the retaining ring and the outer ring retaining groove should be ≤0.1 mm. Do not strike the bearing body. Do not heat to temperatures exceeding 120℃.

Maintenance: Add grease every 500 hours (1/3-1/2 of the bearing cavity volume). Check bearing clearance every 1500 hours (replace if >0.10 mm). Check roller and cage wear every 3000 hours (replace if roller surface peeling/cage deformation). Avoid prolonged exposure to pure axial loads (axial load ≤ 30% of radial load). Prevent foreign objects from entering the bearing.

Troubleshooting: Excessive clearance is mostly due to excessive wear; replace the bearing. Abnormal overheating is mostly due to insufficient lubrication or excessive preload; add grease or adjust the preload. Roller peeling is mostly due to foreign objects entering or overload; replace the bearing and clean the mounting surface.