CAT 280-4445 BUSHING

CAT 280-4445 is a Caterpillar genuine steel wear-resistant bushing (also commonly known as a sleeve bearing), suitable for connecting rods, booms, or bucket pins in excavators/loaders. It reduces friction and wear between the pin and the support. Below are the core information for this genuine part (no alternative parts available):

Core Technical Parameters (Genuine Part Exclusive)

Item Details
Part Model: CAT 280-4445 (2804445) Steel Wear-Resistant Bushing (Suitable for connecting rod/boom/bucket pins, withstands radial loads + low-speed oscillation, genuine design)

Core Material: Ring: 20CrMnTi carburized steel (surface hardness HRC 58–62, carburized layer depth 1.2–1.5 mm), internal self-lubricating groove (3 spiral grooves, groove depth 0.8 mm), compatible with Caterpillar-specific lithium-based grease (NLGI 2)

Key Dimensions: Inner diameter 50 mm, outer diameter 65 mm 70 mm in length, 7.5 mm in wall thickness, inner hole roundness tolerance ≤0.01 mm, mounting surface perpendicularity tolerance ≤0.02 mm
Single weight: Approx. 0.82 kg (1.81 lb)
Compatible models: CAT 320D2/323D2 excavators (boom connecting rod pin), 966M/972M loaders (bucket pin support), compatible pin model 280-4446, often used with 280-4447 sealing rings
Working compatibility: Rated radial load 85 kN, limiting speed 1200 rpm, operating temperature -40℃ to +140℃, suitable for low-speed heavy-load swinging conditions
Core functions and structural features (original factory design):
Heavy-duty wear-resistant: Carburized steel surface hardening treatment, suitable for heavy-duty swinging forces of the boom/bucket pin, original factory carburized layer depth matches the fatigue life design of the whole machine, impact load resistance reaches 120 kN.

Self-lubricating design: Three spiral lubrication grooves in the inner bore ensure even distribution of grease, reducing the coefficient of friction (f≤0.08) and minimizing adhesive wear between the pin and bushing.

Precise fit: The clearance with 280-4446 pins is 0.02–0.03 mm, conforming to Caterpillar’s assembly standards, ensuring smooth and unobstructed movement.

Deformation-resistant reinforcement: Integral forging + precision grinding, uniform wall thickness (tolerance ±0.01 mm), resistant to deformation under heavy loads, with an original factory service life of over 5000 hours.

Installation and maintenance points (original factory specifications)

Installation specifications: Clean the mounting hole, ensuring it is free of rust, oil, and burrs. The hole tolerance is +0.01–+0.02 mm. Use cold pressing (dedicated press), with a pressing force of 8–10 kN. Do not strike the end face.

After installation, check the roundness of the inner hole to ensure it is ≤0.01 mm. Control the clearance with the pin to 0.02–0.03 mm to ensure oscillation accuracy.

Use M10×1.5 bolts (8.8 grade) for fastening, with a torque of 45–50 N·m, to prevent axial movement of the bushing.

Maintenance Recommendations: Check the bushing condition every 800 working hours for wear, cracks, and grease leakage. Replace according to original factory standards.

Use Caterpillar-specific lithium-based grease for lubrication, adding 20–30 g each time, ensuring the lubrication groove is full.

When replacing, always use genuine CAT 280-4445 bushings, and simultaneously replace genuine 280-4446 pins and 280-4447 seals to ensure compatibility and service life.