CAT 103-8442 Spacer

CAT 103-8442 is a Caterpillar genuine steel adjusting shim (precision clearance control shim), compatible with Cat C7.1/C9 engine fuel pump mounts and 320D/323D excavator swing motor flanges. Its core function is to adjust component assembly clearances, compensate for tolerance deviations, and ensure sealing and positioning accuracy. The following are the professional parameters and application guidelines:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes
Model: 103-8442, Type: Steel flat shim (precision adjusting type, no sealing coating, single-sided rust-preventive oil), Compatible with Cat C7.1/C9 engine fuel pump mounts and 320D/323D excavator swing motor flanges, Material: S50C carbon structural steel (quenched, hardness HRC 40-45), Outer diameter: 100 mm, Inner diameter: 50 mm, Thickness: 2.0 mm (tolerance ±0.02 mm), Weight: Approximately 0.19 kg kg, rated bearing pressure ≥200 MPa, operating temperature -40℃ to +150℃, surface roughness Ra≤0.8 μm, flatness ≤0.01 mm, parallelism ≤0.015 mm

Key Dimensions: Outer diameter tolerance ±0.1 mm, inner diameter tolerance ±0.1 mm, thickness tolerance ±0.02 mm, edge chamfer 0.5×45°, suitable mounting surface diameter ≥100 mm, bolt hole distribution circle diameter 75 mm (suitable for M12 bolts), mounting surface flatness ≤0.02 mm

Material and Process: Material S50C carbon structural steel (thickness 2 mm, tensile strength ≥620 MPa), precision stamping + quenching + tempering process, surface galvanized passivation for corrosion protection (film thickness 5-8 μm), no sealing coating, suitable bolt preload ≤120 N・m, can be stacked (maximum 3 pieces) to adjust gap, single piece surface pressure ≥150 MPa Compatible with Cat C7.1/C9 engines (serial number JRE1000-UP) fuel pump mounting bracket and 320D/323D excavators (serial number JBT1000-UP) swing motor flange face. Used to adjust the fuel pump mounting surface clearance (compensating for housing deformation) and the swing motor flange sealing clearance, ensuring fuel pump coaxiality and swing motor sealing performance, and preventing fuel/hydraulic oil leakage. Assembly and Fit: The mounting surface should be clean and free of oil/rust. When using with a sealing gasket (e.g., 383-0423), install the 103-8442 adjusting shim first, then install the sealing gasket. Pre-tighten the bolts symmetrically (in 3 stages, pre-tightening force 80-100 N・m). After installation, flange surface runout ≤0.05 mm, and the clearance should be uniform (deviation ≤0.03 mm). Installation and Maintenance Points: Before installation, check the gasket for deformation, cracks/burrs. Clean the mounting surface and bolt holes, removing oil/rust. Rust and ensure flatness meets requirements.

Adjust the number of shims as required (maximum 3 shims), aligning them with bolt holes when stacking to avoid uneven stress due to misalignment.

Maintenance recommendations: Check the condition of the shims every 1000 hours. Replace them when deformation/rust/wear (thickness reduction > 0.05 mm) is observed. Regularly check bolt torque to prevent loosening and leakage.