CAT 112-8478 BEARING

CAT 112-8478 (1128478) is a Caterpillar original single-row tapered roller bearing, suitable for gearbox/transfer case input shafts/intermediate shafts. The following is purely precise information (no additional description):

Core Parameters and Information

Item Details
Part Model: CAT 112-8478 Single-row tapered roller bearing (outer ring + inner ring + rollers + cage integrated)

Part Type: Heavy-duty tapered roller bearing, bearing radial + unidirectional axial combined loads, suitable for high-speed rotating shaft systems in gearboxes/transfer cases/drive axles, transmitting torque and providing positioning.

Material: Inner ring/outer ring: Chromium bearing steel (GCr15), hardened to HRC60-64; Rollers: GCr15SiMn, ultra-fine ground (Ra≤0.1 μm); Cage: ZL105 cast aluminum, grease groove integrated design

Key Dimensions: Inner diameter 50.80 mm (2.0000 in), outer diameter… 92.075 mm (3.6250 in), width 22.225 mm (0.8750 in), cone angle 10°30′, number of rollers 14, roller diameter 8.73 mm, roller length 18.5 mm, clearance class C3, fit tolerance k5 (inner ring)/H7 (outer ring)

Structural Features: Single row tapered rollers, separable design (inner ring separable), cage-guided rollers, outer ring with locating groove, inner ring with double flanges, grease lubrication suitable, limiting speed 5000 rpm, rated dynamic load 62.5 kN, rated static load 75.0 kN

Compatible Structures: Front bearing of input shaft of mini excavator/loader gearbox, intermediate shaft bearing of transfer case, side bearing of drive axle differential, compatible with bearing housing 112-8479

Applicable Operating Conditions: Suitable for maximum radial load 45 kN, axial load 25 kN, speed… 1000-4500 rpm, oil temperature -30℃ to 120℃, gearbox rotating shaft system without severe impact.
Compatible Models and Assemblies:
Excavators: CAT 305.5, 306, 307 (305.5 gearbox input shaft bearing assembly, 306 transfer case intermediate shaft bearing assembly)
Loaders: CAT 903, 904, 906 (903 gearbox second axle front bearing assembly, 904 drive axle differential side bearing assembly)
Mini Bulldozers: CAT D3K2 (D3K2 transfer case input shaft bearing assembly)
Compatible Assemblies: 305.5 gearbox input shaft bearing assembly, 903 gearbox second axle front bearing assembly, D3K2 transfer case input shaft bearing assembly
Installation and Fitting Points: Before installation, clean the bearings, journals, and bearing housings, checking for cracks, rust, roller jamming, cage deformation, and unobstructed grease grooves.

The inner ring should have an interference fit with the shaft (interference 0.010-0.020 mm), and the outer ring should have a transition fit with the bearing housing (clearance 0.005-0.015 mm). Heat the inner ring to 80-100℃ before heat fitting; do not strike.

After installation, the axial clearance should be 0.05-0.10 mm, and the radial runout ≤0.02 mm. Operation should be smooth without jamming or abnormal noise. The grease filling amount should be 1/3-1/2 of the bearing cavity volume (NLGI Grade 2 lithium-based grease).

Disassembly should be done using a dedicated puller. Remove the inner ring first, then the outer ring, to avoid damage to the journal/bearing housing. Before reuse, check the roller wear (replace if >0.10 mm).