CAT 078-0653 SEAT CHECK

CAT 078-0653 is a Caterpillar original check valve seat, compatible with the fuel system or hydraulic circuit of 3044C/3054C engines, 306E/307E excavators, and 226B3/246B3 skid steer loaders. It is used for one-way shut-off sealing to prevent backflow of media and is often installed in conjunction with 078-0253 retainers and 077-8727 bearings.

Core Parameters and Information

Item Details
Part Model: CAT 078-0653 (078653) Check Seal

Structure Type: Annular seat body, with a central sealing cone surface, and an outer ring with a positioning step; threaded/interference fit installation available.

Material: 42CrMo alloy steel, surface carburized and quenched, conforming to CAT MES B0303 specification.

Key Dimensions: Outer diameter 45 mm, inner diameter 28 mm, height 18 mm, sealing cone angle 30°, positioning step width 5 mm, thread specification M45×1.5

Performance Parameters: Sealing pressure 0-35 MPa, operating temperature -40℃ to +120℃, sealing leakage ≤0.01 mL/min, hardness HRC58-62, surface roughness Ra≤0.8 μm

Compatibility Standard: Compatible with SAE J1926 installation standard, compatible with 078-0253 retainer positioning installation.

Matching Relationship: Compatible with… For use with CAT 3044C/3054C engines, 306E/307E excavators, and 226B3/236B3/246B3 skid steer loaders, compatible with 078-0253 retainers and 077-8727 bearings.

Compatible Models and Application Scenarios

Compatible Equipment: Fuel injection systems or hydraulic pilot circuits of CAT 3044C/3054C engines, 306E/307E mini excavators, and 226B3/236B3/246B3 skid steer loaders.

Application Scenarios: One-way shut-off seal to prevent fuel/hydraulic oil backflow, ensuring stable system pressure, suitable for medium-low pressure, medium-temperature continuous operation.

Installation: Threaded or interference fit installation in the valve body/cylinder seat hole, with the sealing cone surface fitting snugly against the check valve core. After installation, the sealing surface runout should be ≤0.03 mm.

Installation and Maintenance Points:

Clean the check seat, seat bore, and valve core. Check for deformation, cracks, and scratches on the sealing surface. Ensure the clearance between the seat bore and the check seat meets requirements.

Use specialized tools for installation, ensuring the check seat end face is flush with the seat bore without misalignment. Threaded installation torque is 80-100 N·m, and interference fit is 0.01-0.02 mm.

Post-installation inspection: Test with rated pressure medium. No leakage is detected, and the check valve operates smoothly without jamming.

Maintenance: Check for wear and leakage on the sealing surface every 2000 hours. Replace immediately if wear exceeds 0.1 mm or leakage exceeds the standard.