CAT 478-4933 380mm Outer Diameter Bearing Cap

CAT 478-4933 is a Caterpillar original equipment manufacturer (OEM) hydraulic pump drive shaft dust cover (CAP). It is an engineering plastic shaft end protection cover, compatible with the hydraulic pump drive shaft and gearbox secondary shaft ends of Cat 320D2/323D2 excavators and 966M loaders. Its core function is to prevent dust, oil, and foreign object intrusion, protecting the shaft end structure of the 508-5838 retainer and 257-2177 cylindrical roller bearing. It is suitable for low-to-medium speed and light-to-medium load conditions. The following is professional structured information:

Core Technical Parameters (Professional Version)

Item Details Basic Attributes Model 478-4933, Type: Shaft end dust cover (with O-ring seal), Compatible with Cat 320D2/323D2 excavator hydraulic pump drive shaft and 966M loader gearbox secondary shaft ends, Material: PA66 nylon (containing 30% glass fiber reinforcement), Outer Diameter φ85 mm, inner diameter φ80 mm, height 12 mm, single weight approximately 0.08 kg, compatible shaft diameter φ80 mm, operating temperature -40℃ to +120℃, compatible speed ≤3000 rpm, sealing method is O-ring (nitrile rubber NBR, wire diameter 1.5 mm), protection rating IP65, compatible shaft end thread M80×2-6G

Key Dimensions: Outer diameter tolerance +0.10/-0.05 mm, inner diameter tolerance +0.05/-0.05 mm, height tolerance ±0.1 mm, wall thickness 3.0 mm, O-ring groove diameter φ82 mm, groove width 1.6 mm, compatible shaft end chamfer 1.0×45°, cover edge roughness Ra≤1.6 μm, coaxiality ≤0.1 mm, compatible shaft end protrusion length ≥10 mm

Material and Process: PA66 Nylon + 30% glass fiber (flexural strength ≥250 MPa, impact strength ≥8 kJ/m²), UV-resistant surface coating (thickness 5-8 μm), NBR O-ring (hardness 70 Shore A, resistant to hydraulic oil/mineral oil), injection molded cover with burr-free edges, smooth O-ring groove surface, and sealing surface flatness ≤0.05 mm. Fits 508-5838 retainer with an outer diameter of φ80 mm. Compatible with Cat 320D2/323D2 excavator hydraulic pump drive shaft and 966M loader gearbox second shaft end. Protects the shaft end of 508-5838 retainer and 257-2177 cylindrical roller bearings from dust, oil, moisture, and foreign matter. Fits φ80 mm shaft diameter. Installed on the outside of the 508-5838 retainer at the shaft end, fitting flush with the shaft end plane. Assembly fit. The dust cover should have an interference fit with the shaft end (interference 0.05-0.10 mm), O-ring compression 0.3-0.5 mm, rear face runout ≤0.1 mm, and no axial movement. Use a dedicated jaw puller for disassembly; do not pry forcefully to prevent cover breakage.

Installation and Maintenance Points:

Before installation, clean the shaft end surface and check for cracks in the dust cover and damage to the O-ring. Insert the O-ring into the groove of the cover and press it into place by hand until it fits snugly against the shaft end, ensuring the O-ring is fully embedded without twisting.

After installation, check that the dust cover fits tightly against the shaft end without looseness. Check every 1000 hours. Replace the dust cover immediately if it cracks or the O-ring ages.

Maintenance Recommendations: Use Cat HYDO Advanced 10W hydraulic oil. Avoid contact with sharp or hard objects to prevent scratching the cover or O-ring.

Purchasing and Inventory Recommendations