CAT 175-4921 BUSHING

CAT 175-4921 is a Caterpillar genuine straight-tube heavy-duty steel bushing, suitable for the boom, stick, and connecting rod hinges of excavators, loaders, and other equipment. Its core function is to support the pins, withstand radial loads and impacts, reduce friction, and provide positioning, ensuring stable operation of the hinged parts under harsh working conditions.

Cat® 175-4921 is a genuine Caterpillar straight-tube heavy-duty steel bushing. Core Technical Parameters

Item Details
Part Model: CAT 175-4921 Straight Cylinder Bushing, Original Part Number 1754921, Heavy Duty part, no official direct replacement model, suitable for heavy-duty articulated parts (Cat®)…

Material: Alloy structural steel base material, surface carburized and quenched, hardness HRC 58-62, inner hole copper alloy plated, roughness Ra≤0.1μm, wear-resistant and corrosion-resistant, suitable for dusty and humid construction site environments (Cat®)…

Key Dimensions: Inner diameter 70mm, outer diameter 90mm, length 60mm, chamfered ends 1×45°, no inner hole oil groove, interference fit with pin and mounting hole (interference 0.01-0.02mm) to ensure assembly accuracy

Compatible Models: CAT 320D2/336D2 excavators, 966K/972K loaders, D6T bulldozers, etc., for boom… The boom hinge, connecting rod-frame connection, and bucket pin support withstand heavy loads and impact loads.

Performance Characteristics: Rated radial load 80kN, operating temperature -30℃ to 110℃, suitable for low-speed oscillating conditions (≤50r/min). When used with grease, it effectively reduces friction and wear (Cat®…).

Core Functions and Structure:

Heavy-duty support: The straight-tube structure adapts to the radial heavy load of the hinge pin, supporting the pin and limiting radial movement, preventing jamming or component damage due to excessive clearance (Cat®…).

Friction control: The hardened surface and coating design reduce the coefficient of friction between the pin and bushing. Regular lubrication forms an oil film, reducing wear and extending the service life of the hinged parts (Cat®…).

Impact buffering: The alloy material has a certain degree of toughness, absorbing impact loads during hinge operation, protecting the pin and mounting holes, and reducing the risk of fatigue damage (Cat®…).

Installation and Maintenance Points

Installation Specifications: Clean the surfaces of the bushing, pin, and mounting holes to remove oil, rust, and impurities. Inspect the bushing for cracks, deformation, or other defects. Ensure the mounting hole tolerances meet H7 grade requirements (Cat®…).

Use cold or hot fitting methods (heating temperature 80-100℃) to press the bushing into the mounting holes, avoiding direct impact on the bushing end face. After installation, check that the bushing end face runout is ≤0.03mm to ensure coaxiality (Cat®…).

After installation, apply CAT-specific lithium-based grease to ensure the gap between the pin and bushing is filled with grease, preventing dry friction (Cat®…).

Maintenance Recommendations:
Every 500 working hours, check for abnormal noises or looseness at the hinge joints, and for grease leakage. If the bushing inner diameter wear exceeds 0.2mm or the clearance is greater than 0.3mm, replace the (Cat®…) bushing immediately.

Regularly clean impurities from the hinge area to keep the lubrication channels clear. In heavy-duty or dusty environments, the lubrication frequency can be shortened to 250 hours/time for Cat®…