CAT 186-8990 Bearing Retainer with Relief Fitting

CAT 186-8990 is a Caterpillar genuine external retaining ring assembly for shafts, compatible with Cat C15/C18 engines, 777D mining truck transmission systems, and 988H loader differentials. It is an integrated assembly of tempered carbon steel rectangular cross-section external retaining rings, including the retaining ring body, mounting tool slots, and anti-rust coating. Its core function is to secure bearings, gears, seals, and other shaft components, preventing axial movement. The following is a professional technical and application guide:

Core Technical Parameters (Professional Version)

Item Details Basic Attributes Model 186-8990, Type: External retaining ring assembly for shafts (tempered carbon steel rectangular cross-section, with mounting lugs), compatible with Cat C15/C18 engine crankshaft front bearings, 777D mining truck transmission output shafts, and 988H loader differential planetary gear shafts, material: S60C spring steel (HRC 48-52), surface galvanized and passivated (neutral salt spray resistance ≥96 hours), free diameter φ120 mm, shaft diameter compatible with φ120 mm (tolerance h6), retaining ring thickness 3.0 mm, width 4.5 mm, single weight approximately 0.21 kg, rated axial load ≥12 kN, operating temperature -40℃ to +150℃, compatible groove width 4.6 mm (tolerance +0.10/-0.05 mm), groove diameter φ118.5 mm (tolerance ±0.05 mm)

Key dimensions: Free diameter tolerance 0/-0.20 mm, thickness tolerance ±0.05 mm, width tolerance ±0.10 mm, mounting ear height 6.0 mm (tolerance ±0.15 mm), opening clearance 5.0 mm (compressed to 1.5-2.0 mm after installation), retaining ring to groove bottom contact area ≥90%, axial movement ≤0.1 mm after installation

Material and process: S60C spring steel, quenched and tempered at medium temperature (surface hardness HRC) 48-52 mm, elastic modulus 206 GPa), galvanized and passivated surface (corrosion protection), rectangular cross-section design (enhanced load-bearing capacity), mounting ears at both ends (for easy disassembly and installation), free from burrs, cracks, deformation, and other defects. Compatible with Cat C15/C18 industrial engine crankshaft front end, 777D mining truck gearbox output shaft, 988H loader differential planetary gear shaft, and 140M grader steering drive axle. Its core function is to fix bearings, gears, seals, and other shaft components to prevent axial movement. Suitable for medium speed (≤3000 r/min) and medium load conditions, ensuring stable operation of the transmission system. Assembly fit: Clearance fit with shaft groove (0.05-0.10 mm). After installation, the retaining ring is fully embedded in the groove and fits snugly against the end face of adjacent components without gaps. Use Cat-specific retaining ring pliers (model 9S-9042) for installation to avoid deformation or damage to the retaining ring. Installation and maintenance points: Clean the shaft groove and retaining ring assembly before installation, and check the retaining ring for deformation. The shaft groove is free of rust and cracks, with no damage or burrs. The groove width and diameter meet the requirements.

During assembly, use special retaining ring pliers to open the retaining ring and smoothly place it into the shaft groove, ensuring the retaining ring is fully embedded. Check for any jamming or looseness. After installation, use a feeler gauge to measure the axial clearance, ensuring it is ≤0.1 mm.

Maintenance Recommendation: Check the retaining ring condition every 1500 hours. Replace it immediately if deformation, rust, or excessive axial clearance is observed to prevent equipment failure due to loose components.