CAT 039-8729 RETAINER

CAT 039-8729 is a Caterpillar genuine axle retaining ring (pure original factory information, no additional description), compatible with hydraulic pump drive shafts, fan brackets, or gearbox secondary shafts in C7/C9 engines, 320D/323D excavators, 950H/966H loaders, etc. It is used with 039-6449/039-6450 bearings and 038-7406 bearing housings for axial positioning and anti-migration, ensuring reliable fixation of transmission components (Cat®…).

Core Parameters and Information

Item Details
Part Model: CAT 039-8729 (0398729) Shaft-mounted Elastic Retaining Ring (Shaft Snap Ring)

Type: Shaft-mounted, tapered bevel, elastic opening design, suitable for groove installation, normal temperature operation

Material: 65Mn spring steel, quenched (HRC48-52), galvanized and passivated for corrosion protection

Key Dimensions: Suitable shaft diameter 70 mm, groove diameter 68 mm, groove width 2 mm, retaining ring thickness 1.5 mm, free diameter 72 mm, weight 0.018 kg

Load Capacity: Axial rated load 12 kN, elastic deformation ≤0.5 mm, reliable springback after installation, prevents axial movement

Applicable Temperature: -40℃ ～ +150℃, suitable for engine compartment and transmission system temperature environments

Accuracy Grade: Complies with ISO 7093 standard, dimensional tolerance ±0.05 mm, elasticity and toughness meet the assembly requirements of engineering machinery

Installation Method Use snap ring pliers to pry open the groove of the embedded shaft. After installation, the opening gap should be 0.5-1 mm, with no interference.

Compatible Models and Assemblies

Compatible Parts: CAT 039-6449/039-6450 bearings, 038-7406 bearing housings, 039-5618 retaining rings, 038-7407 sealing rings

Compatible Equipment: CAT 320D/323D excavators, 950H/966H loaders, D6R bulldozers, and other models equipped with C7/C9 engines. Used for axial positioning of hydraulic pump input shafts, fan pulley shafts, gearbox secondary shafts, etc.

Matching Parts: 039-8729 retaining rings, 039-6449/039-6450 bearings, 039-5618 retaining rings, 038-7406 bearing housings, 038-7407… Sealing Ring
Installation and Maintenance Points
**Before installation, clean the shaft groove, ensuring it is free of burrs, oil, and rust. Inspect the retaining ring for deformation, cracks, or peeling of the galvanized layer.**
**Use special retaining ring pliers to pry open the retaining ring and insert it into the shaft groove, ensuring it is fully inserted with the opening facing the non-load-bearing end to avoid interference.**
**After installation, check that the retaining ring fits snugly against the bearing end face, with an axial clearance ≤0.1 mm, and no looseness or misalignment.**
**Maintenance: Every 1500 working hours, check the retaining ring’s elasticity and groove fit. Replace immediately if deformed, broken, or corroded to prevent axial movement of components that could cause malfunctions (Cat®…).**