CAT 8I-4419 BEARING-GEAR

CAT 8I-4419 (8I4419) is a Caterpillar cylindrical roller bearing (gear bearing) used in geared transmission systems. It is suitable for heavy-duty gear components such as gearboxes and final drives, providing radial support and positioning. The following is purely precise information (without additional description):

Core Parameters and Information

Item Details
Part Model: CAT 8I-4419 Gear Bearing

Part Type: Single-row cylindrical roller bearing for radial support of gear shafts, suitable for heavy-duty geared transmission systems

Material: Bearing steel (GCr15), outer/inner ring hardened (HRC 60–64), roller surfaces ground, cage made of stamped steel

Key Dimensions: Inner diameter approx. 85.00 mm (3.346 in), outer diameter approx. 150.00 mm (5.906 in), width approx. 35.00 mm (1.378 in), radial clearance C3 group

Structural Features The outer ring has no flange, while the inner ring has double flanges. The separate design allows for a small amount of axial displacement between the shaft and the bearing, accommodating the thermal expansion and contraction of the gear shaft.

Compatible Structure: Matches gear shafts and bearing housings, used for radial support parts such as the second/third shaft of a gearbox and the final drive gear shaft.
Applicable Operating Conditions: High-speed, heavy-load, continuous operation; suitable for gear transmission systems such as gearboxes and final drives in construction machinery.
Compatible Models:
CAT 980G/980H Wheel Loader (Second/Third Shaft Gear Support)
CAT D6R/D6T Bulldozer (Final Drive Gear Shaft Support)
CAT 330C/330D Excavator (Slewing Gearbox Gear Shaft Support)
CAT 777D Mining Dump Truck (Intermediate Shaft Gear Support)
Installation and Fitting Points: The inner ring and shaft have an interference fit (interference 0.015–0.025 mm). Install using the hot-fit method (oil temperature 80–100°C). Direct impact to the bearing body is prohibited.

The outer ring and bearing housing have a clearance fit (0.010–0.020 mm), ensuring the outer ring can move slightly with the thermal expansion and contraction of the shaft.

Before installation, clean the journal and bearing housing bore to remove burrs, rust, and impurities. Inspect the bearing for any bumps or scratches.

Axially, position the bearing against the shaft shoulder and retaining ring to prevent movement. After installation, check for smooth rotation, no abnormal noise, and radial clearance conforming to C3 group standards.

Add the specified gear oil according to the machine manual. Regularly check the oil level and cleanliness to prevent bearing damage due to poor lubrication.

Maintenance and Replacement Instructions:

Every 1000–1500 working hours, check the bearing operating temperature, noise, and vibration. If the temperature rises abnormally (above 80°C), or if abnormal noise or increased vibration occurs, stop the machine immediately for inspection.

Bearings showing signs of peeling, cracks, or uneven roller wear must be replaced.

Non-standard bearings are strictly prohibited from use, as they can cause abnormal wear on the gear shaft and bearing housing, leading to transmission failure or component damage.