CAT 8J-4155 CAP

CAT 8J-4155 is a Caterpillar shaft end dust cover/sealing cover, commonly used on the drive shaft, half shaft, and wheel hub bearing ends of loaders, excavators, mining trucks, and other equipment. It is compatible with Cat 12G/140G graders, 980M loaders, 777G mining trucks, and other models. Its core function is to protect bearings and shaft ends from dust, moisture, and mud, while preventing grease leakage and ensuring the stable operation and lifespan of rotating parts (Cat® Parts). The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 8J-4155, Type: Stamped metal dust cover (with rubber sealing ring), Material: Shell is low carbon steel (SPCC, surface galvanized passivation, corrosion resistant), Sealing ring is nitrile rubber (NBR, oil and temperature resistant), Single weight: approximately 0.23 kg, Applicable temperature: -40℃ to +120℃, Sealing rating: IP65, Suitable speed: ≤3000 rpm, Installation method: Press-fit + snap-fit

Key Dimensions
Outer diameter: 120 mm (tolerance ±0.15 mm), Inner diameter: 80 mm (tolerance 0 to +0.025 mm), Height: 18 mm (tolerance ±0.10 mm), Number of snaps: 6 (evenly distributed), Sealing ring cross-section diameter: 3.5 mm, Suitable shaft diameter: 80 mm (clearance fit, clearance 0.03-0.06 mm), Suitable bearing models include… 435-5200, 487-6168, etc.
Compatible Models and Applications: Compatible with the drive axle half-shaft end of Cat 12G/130G/140G graders, the wheel hub bearing end of 980M loaders, and the drive shaft end of 777G mining trucks. Matching parts include clips, installation fixtures, and grease nipples. Primarily used to protect bearing assemblies, shaft end threads, and seals, preventing premature wear caused by contaminant intrusion.

Performance Parameters: Pressing force 5-8 kN, clip tightening force ≥3 kN, seal ring compression 0.5-1.0 mm, impact vibration resistance ≥10 G, salt spray resistance ≥48 hours, contact gap with bearing end face ≤0.1 mm, no abnormal noise.

Structural and Performance Advantages:
Double protection: The metal outer shell is impact- and wear-resistant; the NBR seal ring tightly fits the shaft surface, providing dustproof, waterproof, and leak-proof protection, suitable for harsh working conditions in construction machinery. Lifespan is approximately twice that of ordinary plastic covers.

Secure Installation: The stamped housing and snap-fit ​​design prevents detachment after press-fitting, adapting to high-speed rotation and vibration environments on the shaft end. No additional fasteners are required after installation, reducing assembly costs.

High Adaptability: Standardized dimensions allow direct replacement of existing covers of the same specification. Compatible with shaft ends and bearing assemblies of various Caterpillar equipment, offering high versatility and convenient inventory management.

Easy Maintenance: Disassembly is achieved using dedicated snap-fit ​​pliers without damaging parts, facilitating bearing inspection and grease replenishment, reducing maintenance time.

Installation and Maintenance Points: Before installation, clean the shaft end, bearing end face, and dust cover, checking for burrs, rust, and deformation. During press-fitting, apply even pressure to the housing end face using a dedicated tooling, ensuring a tight fit between the sealing ring and the shaft surface, and that the snap-fit ​​is fully engaged in the slot. Axial movement after installation should be ≤0.05 mm.

Every 1500 hours of maintenance, check the dust cover for cracks and the sealing ring for aging or damage. If seal failure or housing deformation is observed, replace immediately to prevent contaminant intrusion.

When replacing parts, prioritize original parts to ensure dimensional accuracy and material consistency. Aftermarket parts may cause poor sealing or premature damage due to tolerance or material issues.