CAT 502-6405 BUSHING

CAT 502-6405 is a Caterpillar genuine straight-tube steel bushing, compatible with the boom/stick pins, connecting rods, and swing mechanism of Cat 320D/323D excavators and 950H loaders. It absorbs shock, reduces friction, and positions the pins. The following is pure original data and does not include replacement parts information.

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes
Model 502-6405, Type: Straight cylindrical oil-groove-free steel bushing, Material: 42CrMo alloy steel (surface hardening + nitriding treatment), Single weight: 0.42 kg, Working temperature: -40℃ to +150℃, Allowable radial static load: ≤50 kN, Allowable radial dynamic load: ≤20 kN, Elastic modulus: 206 GPa, Poisson’s ratio: 0.3, Tensile strength: ≥1080 MPa, Yield strength: ≥930 MPa, Hardness: HRC 52-58, Wear-resistant layer thickness: 0.3-0.5 mm, Applicable pin diameter: φ40 mm, Applicable hole diameter: φ45 mm, Rated service life: ≥8000 hours

Key Dimensions
Inner diameter: 40 mm (tolerance +0.025/+0.010 mm), Outer diameter: 45 mm (tolerance 0/-0.015 mm), Length: 50 mm (tolerance ±0.10 mm), wall thickness 2.5 mm (tolerance ±0.05 mm), chamfered ends 0.5×45°, inner hole roughness Ra≤0.8 μm, outer diameter roughness Ra≤1.6 μm, straightness ≤0.03 mm, cylindricity ≤0.02 mm, parallelism of both end faces ≤0.02 mm, perpendicularity of end faces ≤0.02 mm, no oil groove/oil hole (relies on pin lubrication)

Performance parameters: coefficient of friction ≤0.12 (lubricated state), wear rate ≤0.01 mm/1000 hours, compressive strength ≥1800 MPa, shear strength ≥650 MPa, impact toughness ≥12 J/cm², heat resistance temperature ≤200℃ (short-term), assembly interference 0.015-0.030 mm, radial clearance after installation ≤0.05 mm, corrosion resistance: neutral salt spray test ≥48 Rust-free operation for hours.
Structural and performance advantages:

42CrMo alloy steel material: Combining high strength and high toughness, the surface nitriding treatment forms a wear-resistant layer, suitable for high-frequency vibration and heavy-load conditions in engineering machinery, reducing wear on pins and bushings.

Straight cylinder oil-free groove design: Simple structure, convenient installation, suitable for centralized lubrication systems, oil supply through the pin oil passage ensures uniform lubrication and reduces friction loss.

Precise dimensional tolerances: Precise fit clearances between the inner diameter and pin, and between the outer diameter and hole diameter, ensuring no looseness after installation, guaranteeing pin positioning accuracy, and improving the stability of boom/stick movements.

Installation and maintenance points (raw data):

Installation: Clean the mounting holes and pins (free of burrs/oil stains), use cold pressing method for installation (pressing force ≤10 kN), do not heat install (easily causes bushing deformation), after pressing, check that the bushing end face is flush with the mounting surface, radial runout ≤0.05 mm, and the radial clearance after installation is controlled at 0.02-0.05 mm. Maintenance: Check lubrication every 500 hours to ensure unobstructed oil passages. Check bushing wear every 2000 hours (inner diameter wear ≤ 0.2 mm is acceptable). Replace bushings every 8000 hours. Avoid overload operation (≤ 110% of rated load). Use a dedicated puller for disassembly; do not forcefully pry or hammer, as this may damage the mounting holes.

Troubleshooting: Excessive bushing wear is often due to insufficient lubrication; clear the oil passages and replace the bushing. Bushing cracks are often due to overload or misalignment; correct the mounting holes and replace the bushing. Pin misalignment is often due to excessive clearance; adjust the interference fit or replace with a thicker bushing.