CAT 325-6021 Straight Sleeve Bearing

CAT 325-6021 (3256021) is a Caterpillar genuine YM sleeve bearing (sleeve-type sliding bearing with positioning steps), used for radial support and axial positioning of rotating components such as hydraulic pumps and gearboxes. The following is purely precise information (no additional description):

Core Parameters and Information

Item Details
Part Model: CAT 325-6021 YM Sleeve Bearing (with positioning steps, straight cylindrical structure, with lubrication grooves and oil holes)

Part Type: Steel-backed bronze alloy sleeve bearing (bimetallic structure), suitable for medium-low speed, medium-load rotating/oscillating parts, bearing radial loads, providing both positioning and wear resistance, ensuring coaxial operation of components, absorbing impact vibration, and compensating for installation errors and wear.

Material: Steel back: Low carbon steel (Q235, thickness 1.2 mm); Inner liner: Tin bronze ZCuSn5Pb5Zn5 (containing 5% tin, 5% lead, 5% zinc, hardness HB75-95, suitable for grease lubrication); Surface: Circumferential lubrication groove + Axial oil holes for centralized lubrication, ensuring uniform lubrication.

Key Dimensions: Inner diameter 35.00 mm (1.3780 in), outer diameter 42.00 mm (1.6535 in), total length 45.00 mm (1.7717 in), positioning step outer diameter 45.00 mm, thickness 5.00 mm, wall thickness 3.50 mm (0.1378 in), oil hole diameter 2.50 mm (0.0984 in), lubrication groove width 2.00 mm, depth 0.50 mm, number of grooves 4 (circumferentially distributed).

Structural Features: Straight cylindrical structure with positioning steps, bimetallic composite layer (bonding strength ≥140 MPa), built-in lubrication grooves and oil holes, suitable for grease lubrication media, withstands operating conditions from -30℃ to 140℃, suitable for rotary/oscillating motion, precise positioning, long wear-resistant life.

Compatible Structures Hydraulic pump drive shaft support sleeve, gearbox input shaft bearing bushing, fan drive shaft positioning sleeve, steering pump bushing

Applicable working conditions: Suitable for radial load ≤20.0 kN, speed ≤1200 rpm, swing angle ≤±25°, medium to heavy load, medium to low speed, intermittent impact conditions; suitable for rotating/swinging parts of hydraulic and transmission systems in construction machinery.

Compatible models and assemblies:

Excavators: CAT 320D2, 323D2 (hydraulic pump drive shaft sleeve bearing assembly, boom cylinder lug bushing assembly)

Loaders: CAT 938M, 950M (gearbox input shaft sleeve bearing assembly, rocker arm hinge bushing assembly)

Road rollers: CAT CB54, CB64 (vibratory shaft sleeve bearing assembly, travel drive axle bushing assembly)

Compatible assemblies: 320D2 hydraulic pump drive shaft sleeve bearing assembly, 938M gearbox input shaft sleeve bearing assembly, CB54 Vibration Shaft Sleeve Bearing Assembly Installation and Fitting Points: The sleeve and seat bore should have an interference fit (interference 0.008-0.018 mm). Use a dedicated pressing tool for cold pressing installation; direct hammering is prohibited to prevent deformation of the steel backing and peeling of the bronze layer.

Before installation, clean the seat bore, shaft, and sleeve, ensuring they are free of burrs, oil stains, and rust. Inspect the sleeve for cracks and delamination. Align the oil holes with the oil passages in the seat bore, and ensure the positioning step fits snugly against the end face of the seat bore to guarantee accurate positioning and unobstructed lubrication.

After installation, radial runout should be ≤0.02 mm, and the fit clearance 0.04-0.08 mm. Operation/oscillation should be smooth without jamming or abnormal noise. The lubrication system pressure should be normal (2.0-3.5 MPa).

During disassembly, use a dedicated puller to pull out the sleeve evenly. Do not pry forcefully to avoid damaging the seat bore. Before reuse, check for bronze layer wear (replace if wear >0.18 mm).