CAT 118-4770 BUSHING

CAT 118-4770 is a Caterpillar fuel injection pump governor cover bushing, compatible with fuel injection pump governor assemblies for various Cat diesel engines. It supports the shaft, reduces friction, ensures precise positioning of the governor mechanism, and guarantees stable fuel injection quantity and speed control (Cat® Parts Store). The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 118-4770, type is bushing bushing, material is bronze alloy (CuSn8P), surface tin-plated, single weight approximately 0.08 kg, operating temperature -20℃ to +120℃, compatible shaft diameter 12 mm, rated radial load 25 kN, sliding friction coefficient ≤0.08 (lubricated state), fatigue life ≥5000 hours

Key Dimensions
Inner diameter 12.0 mm (tolerance 0/+0.015 mm), outer diameter 18.0 mm (tolerance 0/-0.015 mm), length 15.0 mm (tolerance ±0.10 mm), wall thickness 3.0 mm, chamfer at both ends 0.5×45°, inner hole surface roughness Ra≤0.8 μm, compatible mounting hole diameter 18.0 mm (tolerance +0.015/+0.030) (mm)
Compatible Models and Applications: Compatible with Cat 3126, C7.1, C9 and other diesel engines. Used inside the fuel injection pump governor cover to support the governor shaft. Matching parts are governor cover (118-4771) and shaft (118-4772). Ensures stable operation of the governor mechanism under various working conditions.

Performance Parameters: Wear resistance meets ISO 3547 standards. Under oil lubrication (Cat DEO-ULS 15W-40 engine oil recommended), there is no significant wear after 1000 hours of continuous operation. Corrosion resistance meets ISO 9227 standards, with no rust after 48 hours. Assembly clearance is 0.01-0.03 mm, ensuring smooth shaft rotation without jamming.

Structural and Performance Advantages: Made of bronze alloy, combining good wear resistance and self-lubrication, reducing friction loss between the shaft and bushing, suitable for low-speed reciprocating and rotary motion conditions of the governor shaft.

Tin-plated surface enhances corrosion resistance, making it suitable for the dusty and humid working environment of the engine compartment and extending its service life.

Precise dimensional tolerances and surface roughness control ensure a good fit between the shaft and bushing, maintaining the positioning accuracy of the speed regulator mechanism, ensuring precise control of fuel injection, and improving the stability of engine power output.

Simple structure and easy installation, requiring no complex tools, reduce the difficulty and time cost of maintenance and replacement.

Installation and Maintenance Points: Before installation, clean the governor cover mounting holes and shaft, checking for burrs and scratches; use the cold-fit method, pressing the bushing into the mounting hole with a special press. After pressing, use a dial indicator to check the roundness and coaxiality of the inner hole to ensure compliance. Do not directly strike the bushing.

After installation, apply a small amount of engine oil and check that the shaft rotates freely without jamming. After assembly, the governor cover should seal well with no oil leaks.

Maintenance: Check the governor’s working status every 1000 hours. If there are fluctuations in speed or abnormal fuel injection, check the bushing wear in time. If the wear of the inner hole is greater than 0.05 mm or the surface is scratched or peeled off, replace it immediately. When replacing, you must use original parts to ensure compatibility with the governor assembly.