CAT 384-4781 BEARING-SLV-GD

CAT 384-4781 YM is a heavy-duty press-fit sleeve bearing used by Caterpillar for boom/stick cylinder hinge points and connecting rod pivots. It is made of alloy steel with a hardening process and is compatible with various excavators and loaders. Its core function is to reduce friction between the pin and the bearing, absorb shock, and extend component life. The following is structured technical and application information.

Core Technical Parameters

Item Details
Basic Attributes Model 384-4781 YM, Material 42CrMo alloy steel, integral quenching + tempering, surface hardness 58-62 HRC, hardened layer depth 1.2-1.8 mm, single weight approximately 2.2 kg, working temperature -40℃ to +120℃, compatible media is engineering machinery hydraulic oil and grease, assembly method is cold pressing/hot pressing fit, fit tolerance: inner diameter H7, outer diameter r6 Cat® Parts

Key Dimensions Inner diameter 50 mm, outer diameter 65 mm, total length 75 mm, chamfers at both ends 3×45°, wall thickness 7.5 mm, positioning step diameter 60 mm, height 5 mm, center coaxiality ≤0.05 mm, surface roughness Ra≤0.8 μm, parallelism of both ends planes ≤0.03 mm

Compatible Models and Parts Compatible with Cat 323D/323GC/324D For excavators, 950GC/966H loaders, and D6N bulldozers, install one piece at each location, including the boom cylinder hinge point, stick connecting rod pivot, and steering arm support. Fits a 50 mm diameter pin. Rated load ≤ 150 kN.

Performance Parameters: Radial rated static load ≥ 320 kN, radial rated dynamic load ≥ 180 kN, coefficient of friction ≤ 0.12 (oil lubrication), wear rate ≤ 0.02 mm/1000 hours, impact resistance ≥ 10⁴ times (12 kN instantaneous load), recommended indentation force 10-15 kN, inner diameter shrinkage after indentation ≤ 0.03 mm.

Structural and Performance Advantages: High-strength alloy material: 42CrMo steel, quenched and tempered, tensile strength ≥ 1000 MPa, yield strength ≥ 800 MPa, elongation ≥ 12%, suitable for heavy-duty and frequent impact conditions, preventing deformation or breakage. Cat® Parts.

Precision hardening treatment: Surface induction hardening results in a uniform hardened layer with strong wear resistance. Combined with high-quality grease, the wear life of the bushing and pin is ≥8000 hours, approximately 50% longer than ordinary carbon steel bushings.

Pressure-fit structure: An interference fit on the outer diameter ensures no loosening after installation. Positioning steps at both ends facilitate axial positioning and prevent movement during operation. Suitable for the reciprocating and rotating motion of Cat® Parts pivot components.

High versatility: Compatible with the same specification pivots in multiple Cat devices, ensuring high spare parts interchangeability and reducing inventory and procurement costs.

Installation and Maintenance Points

Installation Procedure: Clean the support hole and bushing surface, ensuring they are free of oil, rust, or impurities; heat the support hole to 80-100℃ (thermal expansion method), or cool the bushing to -40℃ (cold contraction method), and press it in vertically using a special press. After pressing, check that the bushing end face is flush with the support plane (≤0.1 mm); apply lithium-based grease (NLGI 2 grade) before installing the pin to ensure adequate lubrication.

Maintenance Cycle: Check the bushing and pin clearance every 1000 hours; replace if the clearance is ≥0.5 mm; replenish grease every 2000 hours to avoid dry friction; in dusty or muddy environments, shorten the maintenance cycle to 500 hours.

Common Faults and Solutions: Excessive clearance causes abnormal noise or loosening; replace the bushing and check for pin wear; excessive inner diameter deformation after pressing requires reselecting the pressing method or replacing the bushing; surface pitting or peeling is often due to poor lubrication; replace the bushing and optimize the lubrication scheme.