CAT 169-4781 BUSHING

CAT 169-4781 is a Caterpillar genuine straight-tube bimetallic sliding bushing, suitable for heavy-duty pivot joints such as the boom and stick of loaders, excavators, and other equipment. The following are precise original factory specifications and application information; replacement parts are not included.

Core Technical Parameters

Item Details
Part Model: CAT 169-4781 (Straight-tube bimetallic sliding bushing, for heavy-duty joints)
Product Type: Bimetallic composite bushing, steel back + anti-friction alloy layer, suitable for low-speed heavy-duty, oscillating/reciprocating applications
Material: Steel back: Q345B alloy steel; Anti-friction layer: CuPb15Sn8 lead-tin bronze, 5–10 μm tin plating; Steel back thickness: 4 mm; Alloy layer thickness: 2 mm
Key Dimensions: Inner diameter: 80 mm (3.150 in), Outer diameter: 100 mm (3.937 in), Length: 90 mm (3.543 in), Chamfered ends: 1×45°, Wall thickness: 10 mm
Rated Parameters: Rated load capacity: 30 MPa; Suitable linear speed: ≤ 1.5 m/s; Operating temperature: -20℃ ~ +150℃; Coefficient of friction: ≤ 0.07 (oil lubrication)
Unit Weight: Approx. 1.45 kg (3.20 lbs)

Lubrication Adapter: Equipped with axial lubrication grooves and radial oil holes, compatible with lithium-based grease (NLGI 2), and can be continuously supplied via a central lubrication system.

Tolerance Standards: Inner diameter tolerance H7, outer diameter tolerance m6, conforming to ISO 4389 sliding bearing standard.

Structure and Core Features:

Bimetallic Composite Structure: Alloy steel backing provides high rigidity and impact resistance; bronze anti-friction layer has excellent embedding properties, accommodating small impurities and reducing pin wear; tin plating enhances break-in performance and corrosion resistance.

Precision Lubrication Design: The combination of axial lubrication grooves and radial oil holes ensures even distribution of grease on the contact surface, reducing friction and wear, and extending bushing and pin life.

Heavy-Duty Optimization: 10 mm thick-walled design can withstand large radial loads and impacts, suitable for heavy-duty pivot parts such as booms and sticks.

Stable interference fit: Outer diameter tolerance m6, interference fit with mounting hole 0.08–0.15 mm, preventing slippage or loosening during operation and ensuring positioning accuracy.

Compatible Models and Application Scenarios

Compatible Equipment: CAT 938K/950K loaders, 326D/330D excavators, and boom pins, stick pins, connecting rod pins, and other pivot joints on some small bulldozers.

Core Purpose: Installed between the pin and structural components, providing low-friction support, absorbing impact loads, reducing direct wear between the pin and structural components, ensuring smooth joint operation, and reducing maintenance frequency.

Installation and Maintenance Points

Installation: Clean the mounting hole and pin, removing oil, rust, and impurities. Inspect the inner and outer surfaces of the bushing for scratches, porosity, or alloy layer peeling.

Use cold pressing method for installation. Use a special tool to press in evenly, ensuring the bushing end face is flush with the mounting hole end face. Do not strike to avoid deformation.

Post-installation inspection: The clearance between the inner diameter and the pin should be 0.12–0.20 mm; rotation should be smooth without jamming or abnormal noise; the lubrication hole should be aligned with the lubrication system.

Maintenance: Replenish grease every 150–300 hours according to operating conditions to ensure the lubrication grooves and oil holes are unobstructed and avoid dry friction.

If the clearance is >0.4 mm, or if abnormal noise or alloy layer wear occurs, replace the bushing immediately to prevent accelerated wear between the pin and the mounting hole.

Do not use non-original bushings to avoid insufficient load-bearing capacity or premature failure due to incompatible materials or dimensions.