CAT 527-8778 BEARING AS

CAT 527-8778 is a Caterpillar genuine single-row tapered roller bearing assembly (including inner ring, outer ring, rollers, and cage), suitable for heavy-duty transmission components such as the output shaft of the Cat 950GC loader gearbox, the rear axle differential of the 140M grader, and the swing mechanism of the 320D excavator. It can withstand large radial and unidirectional axial loads. The following is its core technology and application information for Cat® Parts:

Core Technical Parameters
Item Details
Basic Attributes Model 527-8778, type is single-row tapered roller bearing assembly (including inner ring, outer ring, rollers, and stamped steel cage), suitable for the output shaft of the Cat 950GC loader gearbox, the rear axle differential of the 140M grader, and the swing mechanism of the 320D excavator; material is inner/outer ring (52100 bearing steel, hardened HRC 60-64), rolling elements (chrome steel, HRC…) 62-66), Cage (SAE 1010 stamped steel, galvanized and passivated), rated dynamic load 112 kN, rated static load 138 kN, limiting speed 3200 rpm (grease lubrication)/4000 rpm (oil lubrication), operating temperature -40℃ to +120℃, contact angle 15°, radial clearance C3 grade (0.020-0.040 mm)

Key Dimensions: Inner diameter 65 mm (2.56 inches, tolerance P6, +0.015/0 mm), outer diameter 120 mm (4.72 inches, tolerance P6, 0/-0.018 mm), width 38 mm (1.50 inches, tolerance ±0.15 mm), chamfer r1/r2=2.5 mm, rolling element diameter 12.2 mm, cage center distance 28 mm

Matching: Fits 65 mm diameter shaft (tolerance…) M6 (+0.019/+0.002 mm), 120 mm diameter bearing housing bore (tolerance H7, +0.040/0 mm). Axial positioning relies on the shaft shoulder and bearing cap. Preload should be adjusted according to the equipment manual. Recommended grease lubrication is Cat DEO-ULS No. 2 lithium-based grease, filling to 1/3-1/2 of the bearing’s internal space. Installation and Maintenance Points: Before installation, clean the shaft and bearing housing bore. Inspect the bearing’s inner and outer rings and rolling elements for cracks/rust, ensure the cage is not deformed, and maintain a shaft and bore surface roughness Ra≤0.8 μm, free from scratches/impacts.

During installation, first heat-fit the inner ring and roller assembly (80-100℃, 5-10 minutes) onto the shaft, then cold-fit the outer ring (-20 to -30℃, 30 minutes) into the bearing housing bore, ensuring the inner and outer ring end faces fit snugly against the shaft shoulder and housing bore step. Adjust the preload according to the equipment manual.

Maintenance recommendations: Check bearing operating temperature (≤80℃) and vibration value (≤2.5 mm/s) every 1000 hours. If grease lubrication is used, add grease every 2000 hours. Replace the bearing immediately if abnormal noise, abnormal temperature rise, or clearance exceeds 0.1 mm.