CAT 078-5251 LOCKING COLL

CAT 078-5251 is a Caterpillar genuine axle locking collar (Type E circlip), compatible with the hydraulic pilot valve assembly (such as the 078-0776 spool valve) of the 3044C/3054C engine, 306E/307E excavator, and 226B3/246B3 skid steer loader. It is used to fix the axial position of components such as the 078-3392/078-3401 bearing, preventing axial movement and ensuring precise and stable valve assembly pressure regulation and reset (Cat®…).

Core Parameters and Information

Item Details
Part Model: CAT 078-5251 (0785251) Locking Ring

Structure Type: Shaft-mounted elastic retaining ring (E-type circlip), single-loop open type, galvanized and passivated surface for corrosion protection

Material: 65Mn spring steel, quenched and tempered, hardness HRC 42-48, galvanized and passivated surface

Key Dimensions: Inner diameter 17 mm, free diameter 18.5 mm, thickness 1.2 mm, opening width 3 mm, compatible shaft groove diameter 17 mm, groove width 1.3 mm

Performance Parameters: Radial spring force ≥55 N, axial load ≥220 N, operating temperature -40℃ to +150℃, salt spray test ≥48 hours without red rust

Compatibility Standards: Complies with ISO 898-1, SAE J429, compatible with 078-0776 slide valve, 078-3392/078-3401 Bearings, 078-2642 retaining springs, and other components.

Compatibility: Suitable for hydraulic pilot valve assemblies and fuel injection control modules of CAT 3044C/3054C engines, 306E/307E excavators, and 226B3/236B3/246B3 skid steer loaders.

Compatible Models and Application Scenarios:

Compatible Equipment: Hydraulic pilot valve assemblies and fuel injection control modules of CAT 3044C/3054C engines, 306E/307E mini excavators, and 226B3/236B3/246B3 skid steer loaders.

Application Scenarios: Installed in the annular groove of the valve core/control shaft, it fits against the end face of the 078-3392/078-3401 bearing to lock the axial position and prevent the bearing and valve core from shifting during rotation and reciprocating motion. Suitable for low-to-medium pressure, medium-speed continuous operation conditions, ensuring rapid valve assembly response and precise positioning. Compatible with: Commonly used with 078-3392/078-3401 bearings, 078-1844/078-5250 locking collars, 078-2642 fixing springs, 078-5198 round stickers, etc., for fixing and marking related components, improving assembly efficiency and accuracy (Cat®…).

Installation and Maintenance Points: Clean the shaft groove and installation tools. Check the collar for deformation, cracks, and corrosion, ensuring good elasticity of the opening.

Use dedicated external snap ring pliers to pry open the collar, align it with the shaft groove, and smoothly insert it, ensuring the collar is fully engaged at the bottom of the groove, conforming to the bearing end face, with no axial looseness.

After installation, check that the axial movement is ≤0.05 mm, there is no risk of the collar falling off, and rotating parts are free from jamming or abnormal noise.

Maintenance: Check the condition of the collar every 2000 hours. Replace it immediately if deformation, wear, or corrosion is found to prevent component displacement and damage due to collar failure.