CAT 478-4931 440mm Outer Diameter Bearing Cap

CAT 478-4931 is a Caterpillar genuine bearing cap/end cap, suitable for drive axle hub bearings or final drive bearings in wheel loaders/excavators. It is used for axial positioning and dust sealing. Each cap weighs approximately 0.85 kg, and one cap is sold per wheel. The following is professional structured information:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes: Model 478-4931, steel bearing cap, suitable bearing outer diameter φ120 mm, positioning inner diameter φ110 mm, sealing groove diameter φ115 mm (suitable for O-rings φ115×3.1 mm), operating temperature -40℃ to +120℃

Key Dimensions: Overall outer diameter φ140 mm, flange thickness 12 mm, cap height 25 mm, 4 flange bolt holes (evenly distributed, diameter φ14 mm, center circle φ125 mm), center positioning hole φ110 mm mm (tolerance + 0.02/-0.01 mm), sealing groove width 3.2 mm, depth 2.8 mm

Material and Process: Q345B low carbon alloy steel (hot rolled, HB 180-200, tensile strength ≥510 MPa), surface galvanized and passivated (corrosion resistant, salt spray test ≥96 h), flange end face flatness ≤0.05 mm, surface roughness Ra≤1.6 μm

Compatible Models: Compatible with drive axle wheel hub bearing end caps or final drive output bearing positioning for Cat 938K, 950GC, 966M wheel loaders, 320GC, 330GC excavators, etc.

Assembly and Fit: The fit clearance with the bearing outer ring end face is ≤0.1 mm, O-ring compression is 0.3-0.5 mm, bolt preload torque is 85-95 N・m, and the anti-loosening method is spring washer + thread locking adhesive (Loctite). 243) Installation and Maintenance Points: Before installation, clean the end cap sealing groove and the bearing outer ring end face, checking for burrs and scratches. Apply lithium-based grease (Cat 106-3962) to the O-ring to ensure a reliable seal.

Align the positioning hole with the bearing outer ring and evenly tighten the four bolts (diagonally, in 2-3 stages to the pre-tightening torque) to avoid uneven loading that could lead to seal failure or bearing damage.

After installation, check for leaks at the contact surface between the end cap and the hub housing, and ensure the hub rotates smoothly without jamming. After 100 hours of operation, retighten the bolts and check for torque decay.

Maintenance Cycle: Check the sealing condition every 500 hours. Replace the O-ring promptly if it is aged, damaged, or the end cap is deformed. It is recommended to replace the O-ring simultaneously with the bearing to ensure positioning accuracy.