CAT 328-5240 Bushing

CAT 328-5240 is a Caterpillar straight-tube steel-backed bronze composite bushing, mainly used in the hinge parts of the boom, stick, and connecting rod of excavators, loaders, and other equipment. It is compatible with Cat 320D, 323D, and 326D excavators, 966M loaders, and other models. It can withstand heavy loads and impacts, and provides stable radial sliding support. It is a core wear-resistant Cat® Part at the hinge of the working device. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 328-5240, Type: Straight-tube composite bushing (no flange), Material: Low-carbon alloy steel backing (base layer hardness HB180-220), Inner liner: High-lead bronze (CuPb10Sn10, surface hardness HB80-100), Single weight: Approximately 0.8 kg, Applicable temperature: -30℃ to +110℃, Maximum bearing pressure: 250 MPa, Coefficient of friction: 0.08-0.12 (oil lubrication), Lubrication method: Grease lubrication (Cat Moly Grease Plus recommended), Accuracy class: ISO H7

Key Dimensions
Inner diameter: 50 mm (tolerance 0 to +0.025 mm), Outer diameter: 60 mm (tolerance 0 to -0.018 mm), Length: 45 mm (tolerance ±0.10 mm), Wall thickness: 5 mm, Inner liner thickness: 1.5 mm, Steel backing thickness: 3.5 mm mm, chamfer 1.5 mm × 45°, fitting shaft diameter 50 mm (recommended clearance fit H9/d9, clearance 0.030-0.065 mm), fitting bore diameter 60 mm (recommended transition fit H7/h6)

Compatible Models and Applications: Compatible with Cat 320D, 323D, 326D excavators, 966M loaders, etc., for hinged parts such as boom pins, stick pins, connecting rod joints, steering knuckle kingpins, etc. Matching parts include pins, dust rings, and lubrication nozzles. Rated radial load ≥90 kN, applicable swing angle ±15°, suitable pin surface hardness HRC50-55

Performance Parameters: 1 lubrication hole (4 mm diameter, located on the side wall), load-bearing method pure radial, impact load ≥30 kN, wear rate ≤0.005 mm/1000 hours, radial runout after assembly ≤0.03 mm, no internal/external runout. External grooves, no intersecting oil holes
Structural and Performance Advantages

Wear-resistant and Durable: A composite structure of steel backing and bronze liner. The steel backing ensures strength, while the bronze liner provides excellent wear resistance and self-lubrication, suitable for harsh working conditions such as dust and vibration in the field. Lifespan is approximately 3 times longer than pure steel sleeves.

Stable Load Bearing: The straight-tube design accommodates the radial load of the hinge pin. The bronze liner absorbs impact and vibration, reducing contact stress between the pin and the bushing and preventing localized wear.

Easy Installation: The flangeless straight-tube structure can be directly pressed into the bearing housing hole. Regular grease injection with a standard lubrication nozzle results in low maintenance costs and suits rapid on-site replacement needs.

High Adaptability: Compatible with the hinge parts of various Caterpillar heavy-duty equipment. High dimensional accuracy allows direct replacement of existing parts of the same specification without modification to the installation structure.

Installation and Maintenance Points:
**Before installation, clean the bushing, pin, and bearing housing bore, checking for burrs, corrosion, and deformation.** During press-fitting, apply even pressure to the steel backing end face using a specialized tool. The pressing force should be ≤40 kN, ensuring a tight fit between the bushing and the housing bore. The rear end face runout should be ≤0.05 mm after installation.

Run the bushing for 1 hour, checking for abnormal noises and overheating. Add grease every 500 hours (approximately 0.15 L each time). Replace the bushing immediately if the inner diameter wear exceeds 0.15 mm or if scratches or peeling appear.

Prioritize original parts for replacement to ensure the bonding strength and dimensional accuracy of the steel backing and bronze liner, avoiding premature wear or breakage due to uneven material properties of aftermarket parts.