CAT 425-6444 BEARING-GD

CAT 425-6444 YM is a Caterpillar construction machinery bimetallic straight-tube sleeve bearing (steel-backed copper bushing). It is suitable for boom/stick hinges and rocker arm connections in small and medium-sized excavators and loaders, supporting the rotation and oscillation of the pin shaft. It is suitable for low to medium loads and low to medium oscillation frequencies. The following is precise technical and application information:

Core Technical Parameters
Item Details
Part Model: CAT 425-6444 (4256444) YM Bimetallic Sleeve Bearing, Suitable for pin shaft diameter 40 mm, Single weight approximately 0.68 kg (1.50 lb)

Core Material: Steel backing (SAE 1045 low-carbon alloy steel) + inner liner (CuSn6Zn6Pb3 tin bronze, containing solid graphite lubricant), steel backing thickness 2 mm, copper layer thickness 1.5 mm, copper layer hardness HB 80-100, coefficient of friction ≤0.15 (lubricated state)

Key Dimensions Inner diameter 40 mm (tolerance H7), outer diameter 47 mm (tolerance g6), total length 50 mm, inner hole with 2 symmetrical axial lubrication grooves, 2 radial oil holes (180° evenly distributed), oil hole diameter 3.5 mm, end face chamfer 1×45°

Rated parameters: Suitable operating temperature -20℃ to +120℃, rated radial load 100 kN, suitable oscillation frequency ≤6 times/minute, suitable pin surface hardness HRC 45-50, installation interference 0.02-0.04 mm

Suitable working conditions: Suitable for medium to low load, medium to low oscillation frequency articulated parts, suitable for grease (NLGI 2 lithium-based grease) lubrication, anti-mud and anti-vibration, suitable for dusty working conditions of construction machinery

Suitable models: CAT 305.5E2/306E2 excavator (stick-link articulation), 906M loader (rocker arm-link articulation) (Boom connection), 226D3 Skid Steer Loader (Bucket-Linkage Connection)

Accessories: Compatible pins 175-4041, bolts 106-7772 (M12×25), grease nipples 1U-8878, with dust rings 453-2166.

Core Functions and Structural Features:

Bimetallic Wear Resistance: Steel backing provides high-strength support; tin bronze liner + graphite self-lubrication reduces pin-bearing friction, suitable for short-term oil-free conditions, and prevents metal-on-metal seizing.

Highly Efficient Lubrication: Axial lubrication grooves + radial oil holes ensure even grease coverage of the inner bore, reducing oscillating wear and extending component life.

Impact Resistance: Bimetallic structure absorbs impact loads at the hinge points, protecting the pins and mounting holes, suitable for vibration conditions in construction machinery.

Easy Installation: Straight cylindrical structure, cold-press installation is possible, suitable for confined spaces, no additional positioning parts required, and old bearings can be directly replaced.

Installation and Maintenance Points

Installation Specifications: Clean the bearing’s inner and outer diameters, mounting holes, and pins. Remove burrs and oil stains. Check the bearing for cracks and copper layer peeling.

Cold press installation: Press-in force ≤ 45 kN. Ensure the bearing end face is flush with the mounting hole end face. After installation, the inner hole roundness ≤ 0.03 mm and coaxiality ≤ 0.05 mm.

After installation, fill with lithium-based grease. Test run: No jamming or abnormal noise; swing clearance ≤ 0.2 mm.

Maintenance Recommendations: Replenish grease every 400 working hours. Check wear every 1200 working hours. Replace immediately if inner hole wear > 0.25 mm or copper layer peeling occurs.

Avoid prolonged dry friction to prevent rapid copper layer wear leading to direct contact between the pin and mounting hole.