CAT 1F-4503 BEARING

The CAT 1F-4503 is a Caterpillar needle roller bearing with a stamped outer ring and no inner ring. It is suitable for rocker arm shafts, pilot valves, and final drive planetary carriers in Cat 3306B engines, 225/235 excavators, and D379/D398 industrial engines. It is used to provide radial heavy-duty support in confined spaces, simplify shaft design and reduce friction. It is a key lightweight load-bearing component in transmission and control mechanisms. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 1F-4503, Type: Needle roller bearing with stamped outer ring and no inner ring (with cage), Material: Outer ring ST12 low carbon steel (zinc-plated and passivated, corrosion resistant ≥48 hours salt spray), Needle rollers GCr15 bearing steel (quenched HRC60-64), Cage PA66+GF25, Single weight approximately 0.09 kg, Applicable temperature -40℃ to +120℃, Compatible grease NLGI 2 lithium-based grease

Key Dimensions
Inner diameter 38.10 mm (compatible shaft diameter tolerance 0/-0.02 mm), Outer diameter 50.80 mm (tolerance 0/-0.04 mm), Width 19.05 mm (tolerance ±0.10 mm), Needle roller diameter 3.97 mm, Number of needle rollers 12, Cage pocket clearance 0.10-0.15 mm, chamfered ends C1×45°, radial runout ≤0.03 mm

Compatible Models and Applications: Compatible with Cat 3306B engine rocker arm shaft support, 225 excavator pilot valve core bearing, D379 industrial engine camshaft support, 953 loader final drive planetary carrier bearing, 1-2 pieces per component, installed between the housing bearing bore and the shaft, bearing radial load and positioning the shaft system.

Performance Parameters: Rated radial dynamic load ≥42 kN, rated radial static load ≥65 kN, fatigue life ≥800 hours (under rated load), limiting speed ≤3000 r/min (grease lubrication), coefficient of friction μ≤0.0015, impact load ≥80 kN (instantaneous)

Structural and Performance Advantages: Compact and heavy-duty: The inner ring-less design allows the shaft to directly serve as the raceway; stamped outer ring + dense needle roller structure, within φ38×51 mm… Achieving high radial load capacity within a small space, increasing load capacity by approximately 40% compared to deep groove ball bearings of the same size.

Lightweight and efficient: The stamped outer ring and plastic cage significantly reduce weight. The large needle roller contact area reduces friction loss by 60% compared to sliding bearings, making it suitable for high-frequency reciprocating or low-speed rotational applications and improving energy efficiency.

Easy installation: The flexible outer ring design allows for cold pressing into the bearing bore (pressure ≤30 kN), eliminating the need for additional positioning components. It achieves a precise interference fit with the original housing bore (interference 0.01-0.03 mm), resulting in high installation efficiency.

High adaptability: Compatible with various machine models and space-constrained shaft systems. The needle roller hardness and cage temperature resistance are suitable for vibration and impact conditions in engineering machinery, reducing maintenance frequency.

Installation and Maintenance Points:
**Before installation, clean the shaft surface (roughness Ra≤0.8 μm) and bearing bore, checking for missing needle rollers and undamaged cage.** Use a special pressure block to cold press the outer ring into place, strictly avoiding striking the outer ring edge. After installation, check for smooth shaft rotation and radial clearance ≤0.05 mm.

Every 800 hours of maintenance: Replenish with lithium-based grease, check for looseness in the outer ring (replace if clearance ≥0.1 mm), and repair or replace the shaft or bearing if shaft surface wear ≥0.03 mm to prevent accelerated needle roller wear.

Prioritize original parts. Aftermarket parts may have insufficient needle roller hardness or low outer ring precision, easily leading to shaft wear or premature bearing failure, causing mechanism jamming.