CAT 303-1299 37.1mm Straight Sleeve Bearing

CAT 303-1299 is a Caterpillar straight-tube press-fit sleeve bearing, suitable for the boom, stick and other hinge parts of excavators, loaders and other equipment. It is used to reduce the friction between the pin and the frame, and is suitable for medium and heavy load, medium speed swing conditions, to ensure the stability of equipment operation and the service life of components. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 303-1299, Type: Straight-tube press-fit sleeve bearing, Material: 4140 alloy steel (carburized and quenched, hardness HRC 60-64), Single weight: approximately 0.85 kg, Operating temperature: -30℃ to +120℃, Design life: ≥10000 hours (normal operating conditions), Suitable for medium-heavy load, medium-speed oscillation (≤12 times/minute) operating conditions, Surface treatment: carburized and quenched + precision grinding, Corrosion resistance meets ISO 12944-5 standard, Impact strength: ≥90 J/cm²

Key Dimensions
Inner diameter: 55 mm (tolerance 0/+0.012 mm), Outer diameter: 70 mm (tolerance 0/-0.018 mm), Total length: 50 mm (tolerance 0/-0.20 mm), Mounting chamfer: r2.0 mm, Wall thickness: 7.5 mm mm, press-fit interference 0.020-0.030 mm (with mounting hole), clearance with pin 0.012-0.022 mm, radial runout ≤0.01 mm
Compatible Models and Parts: Compatible with boom and stick articulation parts of Cat 320D2 and 323D2 excavators, 966M loaders, etc., with 16-2153 pins and 5P-0960 extreme pressure lithium-based grease. Can be used in combination with 389-0698 retainer and 135-2443 sealing ring.
Performance Parameters: Rated load pressure ≥150 MPa, coefficient of friction ≤0.002 (good lubrication conditions), wear layer thickness 1.0-1.5 mm, fatigue life ≥6×10⁵ cycles (rated load)
Structural and Performance Advantages: Made of 4140 alloy steel with carburizing and quenching treatment, hardness reaches HRC The bushing, sized 60-64, combines high wear resistance and impact resistance, making it suitable for harsh working conditions involving heavy loads and frequent oscillations in engineering machinery, extending component lifespan.

Precise dimensional tolerances and a reasonable press-fit interference design ensure a stable fit between the bushing and the mounting hole, preventing loosening. Simultaneously, the appropriate clearance with the pin ensures smooth oscillation, reducing frictional resistance and energy consumption.

The straight-tube structure is suitable for various hinge joints, facilitating easy installation without a complex lubrication system. Regular grease application is sufficient, resulting in low maintenance costs. It also adapts to compact equipment layouts, simplifying the installation process.

Installation and Maintenance Points: Before installation, clean the bushing, mounting hole, and pin, checking for burrs, rust, or deformation. Use a dedicated press-fit tool to smoothly press the bushing into the mounting hole; avoid hammering to prevent bushing deformation or cracking.

After installation, apply appropriate grease to ensure adequate lubrication. Install the elastic retaining ring to secure the pin and prevent axial movement. Before operation, check the smooth oscillation of the hinge joint for any abnormal noises; adjust promptly if any abnormalities are found.

Maintenance: Check lubrication and bushing wear every 600 hours. If the clearance exceeds 0.06 mm or if scratches or peeling appear on the surface, replace immediately. When replacing, check the pin wear at the same time. If the pin diameter wear exceeds 0.04 mm, replace at the same time. Do not mix with bushings of different models.