CAT 314-8639 Straight Sleeve Bearing

CAT 314-8639 is a Caterpillar genuine straight-tube steel sleeve bearing (YM marking, suitable for specific working conditions). It is commonly used in the boom, stick, or connecting rod hinges of excavators and loaders. Its core function is to support the pin, bear radial loads, reduce friction, and provide positioning. It is suitable for medium to heavy-duty oscillating conditions, ensuring smooth operation and precise movement of the hinged parts.

Core Technical Parameters

Item Details
Part Model: CAT 314-8639 Straight Sleeve Bearing, Original Part Number 3148639, YM marking corresponds to specific assembly/working condition adaptation, no official direct replacement model, suitable for medium and heavy load articulated parts

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

Key Dimensions: Inner diameter 75mm, outer diameter 95mm, length 55mm, 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 320D2L/330D2 excavators, 966M/972M loaders, D6N bulldozers, etc., for boom use – The boom hinge, connecting rod-frame connection, and bucket pin support withstand medium to heavy loads and impact loads.

Performance Parameters: Rated radial load 75kN, operating temperature -30℃ to 110℃, suitable for low-speed oscillating conditions (≤50r/min). Using CAT-specific lithium-based grease effectively reduces friction and wear.

Core Functions and Structure:

Radial Support and Positioning: The straight-tube structure adapts to the radial force on the hinge pin, supporting the pin and limiting its radial movement, ensuring the motion accuracy of the hinged part, and preventing jamming or component damage due to excessive clearance.

Friction and Wear Control: The hardened surface and plating design reduce the coefficient of friction between the pin and the sleeve. Regular lubrication forms an oil film, reducing the wear rate and extending the service life of the hinged part.

Load Buffering: The alloy material has a certain degree of toughness, absorbing minor impact loads during hinge operation, protecting the pin and mounting holes, and reducing the risk of fatigue damage.

Installation and Maintenance Points

Installation Specifications
Clean the surfaces of the sleeve, pin, and mounting hole to remove oil, rust, and impurities. Inspect the sleeve for cracks, deformation, or other defects. The mounting hole tolerance should meet H7 grade requirements.

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

After installation, apply CAT-specific lithium-based grease to ensure the gap between the pin and sleeve is filled with grease to prevent dry friction.

Maintenance Recommendations
Check every 500 working hours: for abnormal noises or looseness at the hinge joint, and for grease leakage. If the sleeve inner diameter wear exceeds 0.2mm or the gap is greater than 0.3mm, replace it immediately.

Regularly clean impurities from the hinge joint to maintain unobstructed lubrication channels. In heavy-load or dusty environments, the lubrication frequency can be shortened to 250 hours/time.